Solvent extraction for correction of color and aromatics distribution of heavy neutral base stocks

ABSTRACT

Systems and methods are provided for performing solvent extraction on heavy neutral base stocks. The aromatic extraction can reduce aromatics content while have a reduced or minimized impact on lubricant properties. This can allow, for example, for correction of color and/or haze for heavy neutral base stocks, such as heavy neutral base stocks formed from a deasphalted oil.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser. No. 62/439,937 filed Dec. 29, 2016, which is herein incorporated by reference in its entirety.

FIELD

Systems and methods are provided for production of heavy neutral lubricant oil base stocks, such as heavy neutral base stocks derived from deasphalted oils produced by low severity deasphalting of resid fractions.

BACKGROUND

Lubricant base stocks are one of the higher value products that can be generated from a crude oil or crude oil fraction. The ability to generate lubricant base stocks of a desired quality is often constrained by the availability of a suitable feedstock. For example, most conventional processes for lubricant base stock production involve starting with a crude fraction that has not been previously processed under severe conditions, such as a virgin gas oil fraction from a crude with moderate to low levels of initial sulfur content.

In some situations, a deasphalted oil formed by propane desaphalting of a vacuum resid can be used for additional lubricant base stock production. Deasphalted oils can potentially be suitable for production of heavier base stocks, such as bright stocks. However, the severity of propane deasphalting required in order to make a suitable feed for lubricant base stock production typically results in a yield of only about 30 wt % deasphalted oil relative to the vacuum resid feed.

U.S. Pat. No. 3,414,506 describes methods for making lubricating oils by hydrotreating pentane-alcohol-deasphalted short residue. The methods include performing deasphalting on a vacuum resid fraction with a deasphalting solvent comprising a mixture of an alkane, such as pentane, and one or more short chain alcohols, such as methanol and isopropyl alcohol. The deasphalted oil is then hydrotreated, followed by solvent extraction to perform sufficient VI uplift to form lubricating oils.

U.S. Pat. No. 7,776,206 describes methods for catalytically processing resids and/or deasphalted oils to form bright stock. A resid-derived stream, such as a deasphalted oil, is hydroprocessed to reduce the sulfur content to less than 1 wt % and reduce the nitrogen content to less than 0.5 wt %. The hydroprocessed stream is then fractionated to form a heavier fraction and a lighter fraction at a cut point between 1150° F.-1300° F. (620° C.-705° C.). The lighter fraction is then catalytically processed in various manners to form a bright stock.

SUMMARY

In various aspects, systems and methods are provided for performing solvent extraction on heavy neutral base stocks. The aromatic extraction can reduce aromatics content while have a reduced or minimized impact on lubricant properties. This can allow, for example, for correction of color and/or haze for heavy neutral base stocks, such as heavy neutral base stocks formed from a deasphalted oil.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows an example of a configuration for processing a deasphalted oil to form a lubricant base stock.

FIG. 2 schematically shows another example of a configuration for processing a deasphalted oil to form a lubricant base stock.

FIG. 3 schematically shows another example of a configuration for processing a deasphalted oil to form a lubricant base stock.

FIG. 4 shows results from processing a pentane deasphalted oil at various levels of hydroprocessing severity.

FIG. 5 shows results from processing deasphalted oil in configurations with various combinations of sour hydrocracking and sweet hydrocracking.

FIG. 6 schematically shows an example of a configuration for catalytic processing of deasphalted oil to form lubricant base stocks.

FIG. 7 schematically shows an example of a configuration for block catalytic processing of deasphalted oil to form lubricant base stocks.

FIG. 8 schematically shows an example of a configuration for block catalytic processing of deasphalted oil to form lubricant base stocks.

FIG. 9 schematically shows an example of a configuration for block catalytic processing of deasphalted oil to form lubricant base stocks.

FIG. 10 shows UV absorption spectra from a heavy neutral base stocks with and without aromatic extraction.

DETAILED DESCRIPTION

All numerical values within the detailed description and the claims herein are modified by “about” or “approximately” the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art.

Aromatic Extraction of Heavy Neutral Base Stocks

Some of the difficulties in producing lubricant base stocks, such as heavy neutral base stocks, can be related to formation of haze. Without being bound by any particular theory, it is believed that a variety of factors can result in haze formation in a lubricant base stock, either during processing, immediately after processing, or subsequent to processing (such as after sitting for a period of time). One of the factors that can contribute to haze formation is the presence of aromatics within a heavy neutral sample. For example, if a heavy neutral base stock contains an excess of heavy aromatic compounds, the heavy aromatic compounds may not stay completely in solution after formation of the heavy neutral base stock, which could result in the base stock having a hazy appearance over time.

One example of a lubricant production process that can result in production of heavy neutral base stocks with a high content of aromatic compounds is production of base stocks from deasphalted oils. In particular, deasphalted oils formed using a solvent deasphalting process with a high yield of deasphalted oil (i.e., 50 wt % or greater), can have an increased likelihood of containing high contents of aromatics. It has been discovered that heavy neutral base stock samples, such as heavy neutral base stocks formed derived (at least in part) from a deasphalted oil feed, can be corrected to have a reduced or minimized likelihood of haze formation by performing an aromatic (solvent) extraction process on the heavy neutral base stock. Additionally or alternately, such an aromatic extraction process can be beneficial for removing color from a heavy neutral base stock sample. Without being bound by any particular theory, it is believed that the aromatic extraction can remove unstable molecules, such as high molecular weight polynuclear aromatics and/or multi-core naphthenic molecules. The aromatic extraction can be performed after formation of the heavy neutral base stock, or alternatively the aromatic extraction can be performed at an earlier stage in the formation of the heavy neutral base stock.

The aromatic extraction can be performed using aromatic extraction solvents that are commonly used for solvent extraction during solvent processing to form Group I lubricant base stocks. Examples of suitable solvents can include, but are not limited to, N-methyl-pyrrolidone, furfural, and/or phenol. Any convenient type of solvent contactor can be suitable. The heavy neutral base stock can correspond to a base stock with a kinematic viscosity at 100° C. of 6 cSt to 20 cSt, or 6 cSt to 16 cSt, or 6 cSt to 14 cSt, or 6 cSt to 12 cSt, or 8 cSt to 20 cSt, or 8 cSt to 16 cSt, or 8 cSt to 14 cSt, or 8 cSt to 12 cSt, or 10 cSt to 20 cSt, or 10 cSt to 16 cSt, or 10 cSt to 14 cSt. The viscosity index of the heavy neutral base stock can be at least 80, or at least 90, or at least 100, or at least 110, or at least 120. Additionally or alternately, the viscosity index of the heavy neutral base stock can be 80 to 160, or 80 to 140, or 80 to 120, or 90 to 160, or 90 to 140, or 90 to 120, or 100 to 160, or 100 to 140, or 120 to 160, or 120 to 140.

As an example, a Group II heavy neutral (HN) base stock was made from a hydroprocessed blend of C₅ deasphalted oil and vacuum gas oil. The C₅ deasphalted oil was made from a pentane deasphalting process with a deasphalted oil yield of 75 wt %. The “as made” HN base stock sample had an unusual UV aromatics distribution, and also had more color than desired, with the color corresponding to a yellow hue. The HN sample was solvent extracted with N-methyl-pyrrolidone at conditions corresponding to a 200 vol % solvent treat rate, 1 wt % water content, and a temperature of 100° C. Table A summarizes the properties of the HN sample prior to and after the solvent extraction process.

TABLE A Heavy Neutral Properties Before and After Solvent Extraction Refractive Index 1.4566 1.4553 Total Aromatics  ~2 wt % 0.5-1 wt % 2+ Ring Aromatics >0.25 wt %  <0.1 wt % Viscosity Index 95 96 Mutagenicity Index (MI) 0.65 0 Yield, wt % 100 ~79

As shown in Table A, performing the solvent extraction reduced the yield and the aromatics content of the heavy neutral sample, but the properties of the heavy neutral sample were otherwise similar before and after the solvent extraction. Additionally, the solvent extraction removed the color of the sample, so that post-extraction the heavy neutral sample was water-white. It is noted that although 2+ ring aromatics were removed effectively, a meaningful portion of total aromatics remain in the HN sample after extraction, which is believed to show the selective nature of the extraction process for removing multi-ring structures.

FIG. 10 provides a UV absorptivity profile for the HN sample prior to and after the solvent extraction. FIG. 10 shows a reduction in UV absorptivity at various wavelengths. More generally, prior to an aromatics extraction, a heavy neutral sample can have an absorptivity at 226 nm of at least 0.020, or at least 0.025, or at least 0.030. After extraction, the heavy neutral sample can have an absorptivity at 226 nm of less than 0.020, or less than 0.018, or less than 0.016. Additionally or alternately, prior to an aromatics extraction, a heavy neutral sample can have an absorptivity at 254 nm of at least 0.010, or at least 0.012, or at least 0.014. After extraction, the heavy neutral sample can have an absorptivity at 254 nm of less than 0.010, or less than 0.008, or less than 0.006, or less than 0.004. Additionally or alternately, prior to an aromatics extraction, a heavy neutral sample can have an absorptivity at 275 nm of at least 0.010, or at least 0.012, or at least 0.014. After extraction, the heavy neutral sample can have an absorptivity at 275 nm of less than 0.010, or less than 0.008, or less than 0.006, or less than 0.004. Additionally or alternately, prior to an aromatics extraction, a heavy neutral sample can have an absorptivity at 302 nm of at least 0.020, or at least 0.025, or at least 0.030. After extraction, the heavy neutral sample can have an absorptivity at 302 nm of less than 0.010, or less than 0.008, or less than 0.006, or less than 0.004. Additionally or alternately, prior to an aromatics extraction, a heavy neutral sample can have an absorptivity at 310 nm of at least 0.030, or at least 0.035, or at least 0.040. After extraction, the heavy neutral sample can have an absorptivity at 310 nm of less than 0.010, or less than 0.008, or less than 0.006, or less than 0.004. Additionally or alternately, prior to an aromatics extraction, a heavy neutral sample can have an absorptivity at 325 nm of at least 0.010, or at least 0.012, or at least 0.014. After extraction, the heavy neutral sample can have an absorptivity at 310 nm of less than 0.010, or less than 0.008, or less than 0.006, or less than 0.004.

Overview of Lubricant Base Stock Production from Deasphalted Oil

In various aspects, methods are provided for producing Group I and Group II lubricant base stocks, including Group I and Group II bright stock, from deasphalted oils generated by low severity C₄₊ deasphalting. Low severity deasphalting as used herein refers to deasphalting under conditions that result in a high yield of deasphalted oil (and/or a reduced amount of rejected asphalt or rock), such as a deasphalted oil yield of at least 50 wt % relative to the feed to deasphalting, or at least 55 wt %, or at least 60 wt %, or at least 65 wt %, or at least 70 wt %, or at least 75 wt %. The Group I base stocks (including bright stock) can be formed without performing a solvent extraction on the deasphalted oil. The Group II base stocks (including bright stock) can be formed using a combination of catalytic and solvent processing. In contrast with conventional bright stock produced from deasphalted oil formed at low severity conditions, the Group I and Group II bright stock described herein can be substantially free from haze after storage for extended periods of time. This haze free Group II bright stock can correspond to a bright stock with an unexpected composition.

In various additional aspects, methods are provided for catalytic processing of C₃ deasphalted oils to form Group II bright stock. Forming Group II bright stock by catalytic processing can provide a bright stock with unexpected compositional properties.

Conventionally, crude oils are often described as being composed of a variety of boiling ranges. Lower boiling range compounds in a crude oil correspond to naphtha or kerosene fuels. Intermediate boiling range distillate compounds can be used as diesel fuel or as lubricant base stocks. If any higher boiling range compounds are present in a crude oil, such compounds are considered as residual or “resid” compounds, corresponding to the portion of a crude oil that is left over after performing atmospheric and/or vacuum distillation on the crude oil.

In some conventional processing schemes, a resid fraction can be deasphalted, with the deasphalted oil used as part of a feed for forming lubricant base stocks. In conventional processing schemes a deasphalted oil used as feed for forming lubricant base stocks is produced using propane deasphalting. This propane deasphalting corresponds to a “high severity” deasphalting, as indicated by a typical yield of deasphalted oil of about 40 wt % or less, often 30 wt % or less, relative to the initial resid fraction. In a typical lubricant base stock production process, the deasphalted oil can then be solvent extracted to reduce the aromatics content, followed by solvent dewaxing to form a base stock. The low yield of deasphalted oil is based in part on the inability of conventional methods to produce lubricant base stocks from lower severity deasphalting that do not form haze over time.

In some aspects, it has been discovered that using a mixture of catalytic processing, such as hydrotreatment, and solvent processing, such as solvent dewaxing, can be used to produce lubricant base stocks from deasphalted oil while also producing base stocks that have little or no tendency to form haze over extended periods of time. The deasphalted oil can be produced by deasphalting process that uses a C₄ solvent, a C₅ solvent, a C₆₊ solvent, a mixture of two or more C₄₊ solvents, or a mixture of two or more C₅₊ solvents. The deasphalting process can further correspond to a process with a yield of deasphalted oil of at least 50 wt % for a vacuum resid feed having a T10 distillation point (or optionally a T5 distillation point) of at least 510° C., or a yield of at least 60 wt %, or at least 65 wt %, or at least 70 wt %. It is believed that the reduced haze formation is due in part to the reduced or minimized differential between the pour point and the cloud point for the base stocks and/or due in part to forming a bright stock with a cloud point of −5° C. or less.

For production of Group I base stocks, a deasphalted oil can be hydroprocessed (hydrotreated and/or hydrocracked) under conditions sufficient to achieve a desired viscosity index increase for resulting base stock products. The hydroprocessed effluent can be fractionated to separate lower boiling portions from a lubricant base stock boiling range portion. The lubricant base stock boiling range portion can then be solvent dewaxed to produce a dewaxed effluent. The dewaxed effluent can be separated to form a plurality of base stocks with a reduced tendency (such as no tendency) to form haze over time.

For production of Group II base stocks, in some aspects a deasphalted oil can be hydroprocessed (hydrotreated and/or hydrocracked), so that ˜700° F.+(370° C.+) conversion is 10 wt % to 40 wt %. The hydroprocessed effluent can be fractionated to separate lower boiling portions from a lubricant base stock boiling range portion. The lubricant boiling range portion can then be hydrocracked, dewaxed, and hydrofinished to produce a catalytically dewaxed effluent. Optionally but preferably, the lubricant boiling range portion can be underdewaxed, so that the wax content of the catalytically dewaxed heavier portion or potential bright stock portion of the effluent is at least 6 wt %, or at least 8 wt %, or at least 10 wt %. This underdewaxing can also be suitable for forming light or medium or heavy neutral lubricant base stocks that do not require further solvent upgrading to form haze free base stocks. In this discussion, the heavier portion/potential bright stock portion can roughly correspond to a 538° C.+ portion of the dewaxed effluent. The catalytically dewaxed heavier portion of the effluent can then be solvent dewaxed to form a solvent dewaxed effluent. The solvent dewaxed effluent can be separated to form a plurality of base stocks with a reduced tendency (such as no tendency) to form haze over time, including at least a portion of a Group II bright stock product.

For production of Group II base stocks, in other aspects a deasphalted oil can be hydroprocessed (hydrotreated and/or hydrocracked), so that 370° C.+ conversion is at least 40 wt %, or at least 50 wt %. The hydroprocessed effluent can be fractionated to separate lower boiling portions from a lubricant base stock boiling range portion. The lubricant base stock boiling range portion can then be hydrocracked, dewaxed, and hydrofinished to produce a catalytically dewaxed effluent. The catalytically dewaxed effluent can then be solvent extracted to form a raffinate. The raffinate can be separated to form a plurality of base stocks with a reduced tendency (such as no tendency) to form haze over time, including at least a portion of a Group II bright stock product.

In other aspects, it has been discovered that catalytic processing can be used to produce Group II bright stock with unexpected compositional properties from C₃, C₄, C₅, and/or C₅₊ deasphalted oil. The deasphalted oil can be hydrotreated to reduce the content of heteroatoms (such as sulfur and nitrogen), followed by catalytic dewaxing under sweet conditions. Optionally, hydrocracking can be included as part of the sour hydrotreatment stage and/or as part of the sweet dewaxing stage.

Optionally, the systems and methods described herein can be used in “block” operation to allow for additional improvements in yield and/or product quality. During “block” operation, a deasphalted oil and/or the hydroprocessed effluent from the sour processing stage can be split into a plurality of fractions. The fractions can correspond, for example, to feed fractions suitable for forming a light neutral fraction, a heavy neutral fraction, and a bright stock fraction, or the plurality of fractions can correspond to any other convenient split into separate fractions. The plurality of separate fractions can then be processed separately in the process train (or in the sweet portion of the process train) for forming lubricant base stocks. For example, the light neutral portion of the feed can be processed for a period of time, followed by processing of the heavy neutral portion, followed by processing of a bright stock portion. During the time period when one type of fraction is being processed, storage tanks can be used to hold the remaining fractions.

Block operation can allow the processing conditions in the process train to be tailored to each type of lubricant fraction. For example, the amount of sweet processing stage conversion of the heavy neutral fraction can be lower than the amount of sweet processing stage conversion for the light neutral fraction. This can reflect the fact that heavy neutral lubricant base stocks may not need as high a viscosity index as light neutral base stocks.

Another option for modifying the production of base stocks can be to recycle a portion of at least one lubricant base stock product for further processing in the process train. This can correspond to recycling a portion of a base stock product for further processing in the sour stage and/or recycling a portion of a base stock product for further processing in the corresponding sweet stage. Optionally, a base stock product can be recycled for further processing in a different phase of block operation, such as recycling light neutral base stock product formed during block processing of the heavy neutral fraction for further processing during block processing of the light neutral fraction. The amount of base stock product recycled can correspond to any convenient amount of a base stock product effluent from the fractionator, such as 1 wt % to 50 wt % of a base stock product effluent, or 1 wt % to 20 wt %.

Recycling a portion of a base stock product effluent can optionally be used while operating a lube processing system at higher than typical levels of fuels conversion. When using a conventional feed for lubricant production, conversion of feed relative to 370° C. can be limited to 65 wt % or less. Conversion of more than 65 wt % of a feed relative to 370° C. is typically not favored due to loss of viscosity index with additional conversion. At elevated levels of conversion, the loss of VI with additional conversion is believed to be due to cracking and/or conversion of isoparaffins within a feed. For feeds derived from deasphalted oil, however, the amount of isoparaffins within a feed is lower than a conventional feed. As a result, additional conversion can be performed without loss of VI. In some aspects, converting at least 70 wt % of a feed, or at least 75 wt %, or at least 80 wt % can allow for production of lubricant base stocks with substantially improved cold flow properties while still maintaining the viscosity index of the products at a similar value to the viscosity index at a conventional conversion of 60 wt %.

In various aspects, a variety of combinations of catalytic and/or solvent processing can be used to form lubricant base stocks, including Group II bright stock, from deasphalted oils. These combinations include, but are not limited to:

a) Hydroprocessing of a deasphalted oil under sour conditions (i.e., sulfur content of at least 500 wppm); separation of the hydroprocessed effluent to form at least a lubricant boiling range fraction; and solvent dewaxing of the lubricant boiling range fraction. In some aspects, the hydroprocessing of the deasphalted oil can correspond to hydrotreatment, hydrocracking, or a combination thereof.

b) Hydroprocessing of a deasphalted oil under sour conditions (i.e., sulfur content of at least 500 wppm); separation of the hydroprocessed effluent to form at least a lubricant boiling range fraction; and catalytic dewaxing of the lubricant boiling range fraction under sweet conditions (i.e., 500 wppm or less sulfur). The catalytic dewaxing can optionally correspond to catalytic dewaxing using a dewaxing catalyst with a pore size greater than 8.4 Angstroms. Optionally, the sweet processing conditions can further include hydrocracking, noble metal hydrotreatment, and/or hydrofinishing. The optional hydrocracking, noble metal hydrotreatment, and/or hydrofinishing can occur prior to and/or after or after catalytic dewaxing. For example, the order of catalytic processing under sweet processing conditions can be noble metal hydrotreating followed by hydrocracking followed by catalytic dewaxing.

c) The process of b) above, followed by performing an additional separation on at least a portion of the catalytically dewaxed effluent. The additional separation can correspond to solvent dewaxing, solvent extraction (such as solvent extraction with furfural or n-methylpyrollidone), a physical separation such as ultracentrifugation, or a combination thereof.

d) The process of a) above, followed by catalytic dewaxing (sweet conditions) of at least a portion of the solvent dewaxed product. Optionally, the sweet processing conditions can further include hydrotreating (such as noble metal hydrotreating), hydrocracking and/or hydrofinishing. The additional sweet hydroprocessing can be performed prior to and/or after the catalytic dewaxing.

Group I base stocks or base oils are defined as base stocks with less than 90 wt % saturated molecules and/or at least 0.03 wt % sulfur content. Group I base stocks also have a viscosity index (VI) of at least 80 but less than 120. Group II base stocks or base oils contain at least 90 wt % saturated molecules and less than 0.03 wt % sulfur. Group II base stocks also have a viscosity index of at least 80 but less than 120. Group III base stocks or base oils contain at least 90 wt % saturated molecules and less than 0.03 wt % sulfur, with a viscosity index of at least 120.

In some aspects, a Group III base stock as described herein may correspond to a Group III+ base stock. Although a generally accepted definition is not available, a Group III+ base stock can generally correspond to a base stock that satisfies the requirements for a Group III base stock while also having at least one property that is enhanced relative to a Group III specification. The enhanced property can correspond to, for example, having a viscosity index that is substantially greater than the required specification of 120, such as a Group III base stock having a VI of at least 130, or at least 135, or at least 140. Similarly, in some aspects, a Group II base stock as described herein may correspond to a Group II+ base stock. Although a generally accepted definition is not available, a Group II+ base stock can generally correspond to a base stock that satisfies the requirements for a Group II base stock while also having at least one property that is enhanced relative to a Group II specification. The enhanced property can correspond to, for example, having a viscosity index that is substantially greater than the required specification of 80, such as a Group II base stock having a VI of at least 103, or at least 108, or at least 113.

In the discussion below, a stage can correspond to a single reactor or a plurality of reactors. Optionally, multiple parallel reactors can be used to perform one or more of the processes, or multiple parallel reactors can be used for all processes in a stage. Each stage and/or reactor can include one or more catalyst beds containing hydroprocessing catalyst. Note that a “bed” of catalyst in the discussion below can refer to a partial physical catalyst bed. For example, a catalyst bed within a reactor could be filled partially with a hydrocracking catalyst and partially with a dewaxing catalyst. For convenience in description, even though the two catalysts may be stacked together in a single catalyst bed, the hydrocracking catalyst and dewaxing catalyst can each be referred to conceptually as separate catalyst beds.

In this discussion, conditions may be provided for various types of hydroprocessing of feeds or effluents. Examples of hydroprocessing can include, but are not limited to, one or more of hydrotreating, hydrocracking, catalytic dewaxing, and hydrofinishing/aromatic saturation. Such hydroprocessing conditions can be controlled to have desired values for the conditions (e.g., temperature, pressure, LHSV, treat gas rate) by using at least one controller, such as a plurality of controllers, to control one or more of the hydroprocessing conditions. In some aspects, for a given type of hydroprocessing, at least one controller can be associated with each type of hydroprocessing condition. In some aspects, one or more of the hydroprocessing conditions can be controlled by an associated controller. Examples of structures that can be controlled by a controller can include, but are not limited to, valves that control a flow rate, a pressure, or a combination thereof; heat exchangers and/or heaters that control a temperature; and one or more flow meters and one or more associated valves that control relative flow rates of at least two flows. Such controllers can optionally include a controller feedback loop including at least a processor, a detector for detecting a value of a control variable (e.g., temperature, pressure, flow rate, and a processor output for controlling the value of a manipulated variable (e.g., changing the position of a valve, increasing or decreasing the duty cycle and/or temperature for a heater). Optionally, at least one hydroprocessing condition for a given type of hydroprocessing may not have an associated controller.

In this discussion, unless otherwise specified a lubricant boiling range fraction corresponds to a fraction having an initial boiling point or alternatively a T5 boiling point of at least about 370° C. (˜700° F.). A distillate fuel boiling range fraction, such as a diesel product fraction, corresponds to a fraction having a boiling range from about 193° C. (375° F.) to about 370° C. (˜700° F.). Thus, distillate fuel boiling range fractions (such as distillate fuel product fractions) can have initial boiling points (or alternatively T5 boiling points) of at least about 193° C. and final boiling points (or alternatively T95 boiling points) of about 370° C. or less. A naphtha boiling range fraction corresponds to a fraction having a boiling range from about 36° C. (122° F.) to about 193° C. (375° F.) to about 370° C. (˜700° F.). Thus, naphtha fuel product fractions can have initial boiling points (or alternatively T5 boiling points) of at least about 36° C. and final boiling points (or alternatively T95 boiling points) of about 193° C. or less. It is noted that 36° C. roughly corresponds to a boiling point for the various isomers of a C5 alkane. A fuels boiling range fraction can correspond to a distillate fuel boiling range fraction, a naphtha boiling range fraction, or a fraction that includes both distillate fuel boiling range and naphtha boiling range components. Light ends are defined as products with boiling points below about 36° C., which include various C1-C4 compounds. When determining a boiling point or a boiling range for a feed or product fraction, an appropriate ASTM test method can be used, such as the procedures described in ASTM D2887, D2892, and/or D86. Preferably, ASTM D2887 should be used unless a sample is not appropriate for characterization based on ASTM D2887. For example, for samples that will not completely elute from a chromatographic column, ASTM D7169 can be used.

Feedstocks

In various aspects, at least a portion of a feedstock for processing as described herein can correspond to a vacuum resid fraction or another type 950° F.+(510° C.+) or 1000° F.+(538° C.+) fraction. Another example of a method for forming a 950° F.+(510° C.+) or 1000° F.+(538° C.+) fraction is to perform a high temperature flash separation. The 950° F.+(510° C.+) or 1000° F.+(538° C.+) fraction formed from the high temperature flash can be processed in a manner similar to a vacuum resid.

A vacuum resid fraction or a 950° F.+(510° C.+) fraction formed by another process (such as a flash fractionation bottoms or a bitumen fraction) can be deasphalted at low severity to form a deasphalted oil. Optionally, the feedstock can also include a portion of a conventional feed for lubricant base stock production, such as a vacuum gas oil.

A vacuum resid (or other 510° C.+) fraction can correspond to a fraction with a T5 distillation point (ASTM D2892, or ASTM D7169 if the fraction will not completely elute from a chromatographic system) of at least about 900° F. (482° C.), or at least 950° F. (510° C.), or at least 1000° F. (538° C.). Alternatively, a vacuum resid fraction can be characterized based on a T10 distillation point (ASTM D2892/D7169) of at least about 900° F. (482° C.), or at least 950° F. (510° C.), or at least 1000° F. (538° C.).

Resid (or other 510° C.+) fractions can be high in metals. For example, a resid fraction can be high in total nickel, vanadium and iron contents. In an aspect, a resid fraction can contain at least 0.00005 grams of Ni/V/Fe (50 wppm) or at least 0.0002 grams of Ni/V/Fe (200 wppm) per gram of resid, on a total elemental basis of nickel, vanadium and iron. In other aspects, the heavy oil can contain at least 500 wppm of nickel, vanadium, and iron, such as up to 1000 wppm or more.

Contaminants such as nitrogen and sulfur are typically found in resid (or other 510° C.+) fractions, often in organically-bound form. Nitrogen content can range from about 50 wppm to about 10,000 wppm elemental nitrogen or more, based on total weight of the resid fraction. Sulfur content can range from 500 wppm to 100,000 wppm elemental sulfur or more, based on total weight of the resid fraction, or from 1000 wppm to 50,000 wppm, or from 1000 wppm to 30,000 wppm.

Still another method for characterizing a resid (or other 510° C.+) fraction is based on the Conradson carbon residue (CCR) of the feedstock. The Conradson carbon residue of a resid fraction can be at least about 5 wt %, such as at least about 10 wt % or at least about 20 wt %. Additionally or alternately, the Conradson carbon residue of a resid fraction can be about 50 wt % or less, such as about 40 wt % or less or about 30 wt % or less.

In some aspects, a vacuum gas oil fraction can be co-processed with a deasphalted oil. The vacuum gas oil can be combined with the deasphalted oil in various amounts ranging from 20 parts (by weight) deasphalted oil to 1 part vacuum gas oil (i.e., 20:1) to 1 part deasphalted oil to 1 part vacuum gas oil. In some aspects, the ratio of deasphalted oil to vacuum gas oil can be at least 1:1 by weight, or at least 1.5:1, or at least 2:1. Typical (vacuum) gas oil fractions can include, for example, fractions with a T5 distillation point to T95 distillation point of 650° F. (343° C.)-1050° F. (566° C.) or 650° F. (343° C.)-1000° F. (538° C.) or 650° F. (343° C.)-950° F. (510° C.) or 650° F. (343° C.)-900° F. (482° C.) or ˜700° F. (370° C.)-1050° F. (566° C.) or ˜700° F. (370° C.)-1000° F. (538° C.) or ˜700° F. (370° C.)-950° F. (510° C.) or ˜700° F. (370° C.)-900° F. (482° C.), or 750° F. (399° C.)-1050° F. (566° C.), or 750° F. (399° C.)-1000° F. (538° C.), or 750° F. (399° C.)-950° F. (510° C.), or 750° F. (399° C.)-900° F. (482° C.). For example a suitable vacuum gas oil fraction can have a T5 distillation point of at least 343° C. and a T95 distillation point of 566° C. or less; or a T10 distillation point of at least 343° C. and a T90 distillation point of 566° C. or less; or a T5 distillation point of at least 370° C. and a T95 distillation point of 566° C. or less; or a T5 distillation point of at least 343° C. and a T95 distillation point of 538° C. or less.

Solvent Deasphalting

Solvent deasphalting is a solvent extraction process. In some aspects, suitable solvents for methods as described herein include alkanes or other hydrocarbons (such as alkenes) containing 4 to 7 carbons per molecule. Examples of suitable solvents include n-butane, isobutane, n-pentane, C₄₊ alkanes, C₅₊ alkanes, C₄₊ hydrocarbons, and C₅₊ hydrocarbons. In other aspects, suitable solvents can include C₃ hydrocarbons, such as propane. In such other aspects, examples of suitable solvents include propane, n-butane, isobutane, n-pentane, C₃₊ alkanes, C₄₊ alkanes, C₅₊ alkanes, C₃₊ hydrocarbons, C₄₊ hydrocarbons, and C₅₊ hydrocarbons.

In this discussion, a solvent comprising C_(n) (hydrocarbons) is defined as a solvent composed of at least 80 wt % of alkanes (hydrocarbons) having n carbon atoms, or at least 85 wt %, or at least 90 wt %, or at least 95 wt %, or at least 98 wt %. Similarly, a solvent comprising C_(n+) (hydrocarbons) is defined as a solvent composed of at least 80 wt % of alkanes (hydrocarbons) having n or more carbon atoms, or at least 85 wt %, or at least 90 wt %, or at least 95 wt %, or at least 98 wt %.

In this discussion, a solvent comprising C_(n) alkanes (hydrocarbons) is defined to include the situation where the solvent corresponds to a single alkane (hydrocarbon) containing n carbon atoms (for example, n=3, 4, 5, 6, 7) as well as the situations where the solvent is composed of a mixture of alkanes (hydrocarbons) containing n carbon atoms. Similarly, a solvent comprising C_(n+) alkanes (hydrocarbons) is defined to include the situation where the solvent corresponds to a single alkane (hydrocarbon) containing n or more carbon atoms (for example, n=3, 4, 5, 6, 7) as well as the situations where the solvent corresponds to a mixture of alkanes (hydrocarbons) containing n or more carbon atoms. Thus, a solvent comprising C₄₊ alkanes can correspond to a solvent including n-butane; a solvent include n-butane and isobutane; a solvent corresponding to a mixture of one or more butane isomers and one or more pentane isomers; or any other convenient combination of alkanes containing 4 or more carbon atoms. Similarly, a solvent comprising C₅₊ alkanes (hydrocarbons) is defined to include a solvent corresponding to a single alkane (hydrocarbon) or a solvent corresponding to a mixture of alkanes (hydrocarbons) that contain 5 or more carbon atoms. Alternatively, other types of solvents may also be suitable, such as supercritical fluids. In various aspects, the solvent for solvent deasphalting can consist essentially of hydrocarbons, so that at least 98 wt % or at least 99 wt % of the solvent corresponds to compounds containing only carbon and hydrogen. In aspects where the deasphalting solvent corresponds to a C₄₊ deasphalting solvent, the C₄₊ deasphalting solvent can include less than 15 wt % propane and/or other C₃ hydrocarbons, or less than 10 wt %, or less than 5 wt %, or the C₄₊ deasphalting solvent can be substantially free of propane and/or other C₃ hydrocarbons (less than 1 wt %). In aspects where the deasphalting solvent corresponds to a C₅₊ deasphalting solvent, the C₅₊ deasphalting solvent can include less than 15 wt % propane, butane and/or other C₃-C₄ hydrocarbons, or less than 10 wt %, or less than 5 wt %, or the C₅₊ deasphalting solvent can be substantially free of propane, butane, and/or other C₃-C₄ hydrocarbons (less than 1 wt %). In aspects where the deasphalting solvent corresponds to a C₃₊ deasphalting solvent, the C₃₊ deasphalting solvent can include less than 10 wt % ethane and/or other C₂ hydrocarbons, or less than 5 wt %, or the C₃₊ deasphalting solvent can be substantially free of ethane and/or other C₂ hydrocarbons (less than 1 wt %).

Deasphalting of heavy hydrocarbons, such as vacuum resids, is known in the art and practiced commercially. A deasphalting process typically corresponds to contacting a heavy hydrocarbon with an alkane solvent (propane, butane, pentane, hexane, heptane etc and their isomers), either in pure form or as mixtures, to produce two types of product streams. One type of product stream can be a deasphalted oil extracted by the alkane, which is further separated to produce deasphalted oil stream. A second type of product stream can be a residual portion of the feed not soluble in the solvent, often referred to as rock or asphaltene fraction. The deasphalted oil fraction can be further processed into make fuels or lubricants. The rock fraction can be further used as blend component to produce asphalt, fuel oil, and/or other products. The rock fraction can also be used as feed to gasification processes such as partial oxidation, fluid bed combustion or coking processes. The rock can be delivered to these processes as a liquid (with or without additional components) or solid (either as pellets or lumps).

During solvent deasphalting, a resid boiling range feed (optionally also including a portion of a vacuum gas oil feed) can be mixed with a solvent. Portions of the feed that are soluble in the solvent are then extracted, leaving behind a residue with little or no solubility in the solvent. The portion of the deasphalted feedstock that is extracted with the solvent is often referred to as deasphalted oil. Typical solvent deasphalting conditions include mixing a feedstock fraction with a solvent in a weight ratio of from about 1:2 to about 1:10, such as about 1:8 or less. Typical solvent deasphalting temperatures range from 40° C. to 200° C., or 40° C. to 150° C., depending on the nature of the feed and the solvent. The pressure during solvent deasphalting can be from about 50 psig (345 kPag) to about 500 psig (3447 kPag).

It is noted that the above solvent deasphalting conditions represent a general range, and the conditions will vary depending on the feed. For example, under typical deasphalting conditions, increasing the temperature can tend to reduce the yield while increasing the quality of the resulting deasphalted oil. Under typical deasphalting conditions, increasing the molecular weight of the solvent can tend to increase the yield while reducing the quality of the resulting deasphalted oil, as additional compounds within a resid fraction may be soluble in a solvent composed of higher molecular weight hydrocarbons. Under typical deasphalting conditions, increasing the amount of solvent can tend to increase the yield of the resulting deasphalted oil. As understood by those of skill in the art, the conditions for a particular feed can be selected based on the resulting yield of deasphalted oil from solvent deasphalting. In aspects where a C₃ deasphalting solvent is used, the yield from solvent deasphalting can be 40 wt % or less. In some aspects, C₄ deasphalting can be performed with a yield of deasphalted oil of 50 wt % or less, or 40 wt % or less. In various aspects, the yield of deasphalted oil from solvent deasphalting with a C₄₊ solvent can be at least 50 wt % relative to the weight of the feed to deasphalting, or at least 55 wt %, or at least 60 wt % or at least 65 wt %, or at least 70 wt %. In aspects where the feed to deasphalting includes a vacuum gas oil portion, the yield from solvent deasphalting can be characterized based on a yield by weight of a 950° F.+(510° C.) portion of the deasphalted oil relative to the weight of a 510° C.+ portion of the feed. In such aspects where a C₄₊ solvent is used, the yield of 510° C.+ deasphalted oil from solvent deasphalting can be at least 40 wt % relative to the weight of the 510° C.+ portion of the feed to deasphalting, or at least 50 wt %, or at least 55 wt %, or at least 60 wt % or at least 65 wt %, or at least 70 wt %. In such aspects where a C⁴⁻ solvent is used, the yield of 510° C.+ deasphalted oil from solvent deasphalting can be 50 wt % or less relative to the weight of the 510° C.+ portion of the feed to deasphalting, or 40 wt % or less, or 35 wt % or less.

Hydrotreating and Hydrocracking

After deasphalting, the deasphalted oil (and any additional fractions combined with the deasphalted oil) can undergo further processing to form lubricant base stocks. This can include hydrotreatment and/or hydrocracking to remove heteroatoms to desired levels, reduce Conradson Carbon content, and/or provide viscosity index (VI) uplift. Depending on the aspect, a deasphalted oil can be hydroprocessed by hydrotreating, hydrocracking, or hydrotreating and hydrocracking. Optionally, one or more catalyst beds and/or stages of demetallization catalyst can be included prior to the initial bed of hydrotreating and/or hydrocracking catalyst. Optionally, the hydroprocessing can further include exposing the deasphalted oil to a base metal aromatic saturation catalyst. It is noted that a base metal aromatic saturation catalyst can sometimes be similar to a lower activity hydrotreating catalyst.

The deasphalted oil can be hydrotreated and/or hydrocracked with little or no solvent extraction being performed prior to and/or after the deasphalting. As a result, the deasphalted oil feed for hydrotreatment and/or hydrocracking can have a substantial aromatics content. In various aspects, the aromatics content of the deasphalted oil feed can be at least 50 wt %, or at least 55 wt %, or at least 60 wt %, or at least 65 wt %, or at least 70 wt %, or at least 75 wt %, such as up to 90 wt % or more. Additionally or alternately, the saturates content of the deasphalted oil feed can be 50 wt % or less, or 45 wt % or less, or 40 wt % or less, or 35 wt % or less, or 30 wt % or less, or 25 wt % or less, such as down to 10 wt % or less. In this discussion and the claims below, the aromatics content and/or the saturates content of a fraction can be determined based on ASTM D7419.

The reaction conditions during demetallization and/or hydrotreatment and/or hydrocracking of the deasphalted oil (and optional vacuum gas oil co-feed) can be selected to generate a desired level of conversion of a feed. Any convenient type of reactor, such as fixed bed (for example trickle bed) reactors can be used. Conversion of the feed can be defined in terms of conversion of molecules that boil above a temperature threshold to molecules below that threshold. The conversion temperature can be any convenient temperature, such as ˜700° F. (370° C.) or 1050° F. (566° C.). The amount of conversion can correspond to the total conversion of molecules within the combined hydrotreatment and hydrocracking stages for the deasphalted oil. Suitable amounts of conversion of molecules boiling above 1050° F. (566° C.) to molecules boiling below 566° C. include 30 wt % to 90 wt % conversion relative to 566° C., or 30 wt % to 80 wt %, or 30 wt % to 70 wt %, or 40 wt % to 90 wt %, or 40 wt % to 80 wt %, or 40 wt % to 70 wt %, or 50 wt % to 90 wt %, or 50 wt % to 80 wt %, or 50 wt % to 70 wt %. In particular, the amount of conversion relative to 566° C. can be 30 wt % to 90 wt %, or 30 wt % to 70 wt %, or 50 wt % to 90 wt %. Additionally or alternately, suitable amounts of conversion of molecules boiling above ˜700° F. (370° C.) to molecules boiling below 370° C. include 10 wt % to 70 wt % conversion relative to 370° C., or 10 wt % to 60 wt %, or 10 wt % to 50 wt %, or 20 wt % to 70 wt %, or 20 wt % to 60 wt %, or 20 wt % to 50 wt %, or 30 wt % to 70 wt %, or 30 wt % to 60 wt %, or 30 wt % to 50 wt %. In particular, the amount of conversion relative to 370° C. can be 10 wt % to 70 wt %, or 20 wt % to 50 wt %, or 30 wt % to 60 wt %.

The hydroprocessed deasphalted oil can also be characterized based on the product quality. After hydroprocessing (hydrotreating and/or hydrocracking), the hydroprocessed deasphalted oil can have a sulfur content of 200 wppm or less, or 100 wppm or less, or 50 wppm or less (such as down to ˜0 wppm). Additionally or alternately, the hydroprocessed deasphalted oil can have a nitrogen content of 200 wppm or less, or 100 wppm or less, or 50 wppm or less (such as down to ˜0 wppm). Additionally or alternately, the hydroprocessed deasphalted oil can have a Conradson Carbon residue content of 1.5 wt % or less, or 1.0 wt % or less, or 0.7 wt % or less, or 0.1 wt % or less, or 0.02 wt % or less (such as down to ˜0 wt %). Conradson Carbon residue content can be determined according to ASTM D4530.

In various aspects, a feed can initially be exposed to a demetallization catalyst prior to exposing the feed to a hydrotreating catalyst. Deasphalted oils can have metals concentrations (Ni+V+Fe) on the order of 10-100 wppm. Exposing a conventional hydrotreating catalyst to a feed having a metals content of 10 wppm or more can lead to catalyst deactivation at a faster rate than may desirable in a commercial setting. Exposing a metal containing feed to a demetallization catalyst prior to the hydrotreating catalyst can allow at least a portion of the metals to be removed by the demetallization catalyst, which can reduce or minimize the deactivation of the hydrotreating catalyst and/or other subsequent catalysts in the process flow. Commercially available demetallization catalysts can be suitable, such as large pore amorphous oxide catalysts that may optionally include Group VI and/or Group VIII non-noble metals to provide some hydrogenation activity.

In various aspects, the deasphalted oil can be exposed to a hydrotreating catalyst under effective hydrotreating conditions. The catalysts used can include conventional hydroprocessing catalysts, such as those comprising at least one Group VIII non-noble metal (Columns 8-10 of IUPAC periodic table), preferably Fe, Co, and/or Ni, such as Co and/or Ni; and at least one Group VI metal (Column 6 of IUPAC periodic table), preferably Mo and/or W. Such hydroprocessing catalysts optionally include transition metal sulfides that are impregnated or dispersed on a refractory support or carrier such as alumina and/or silica. The support or carrier itself typically has no significant/measurable catalytic activity. Substantially carrier- or support-free catalysts, commonly referred to as bulk catalysts, generally have higher volumetric activities than their supported counterparts.

The catalysts can either be in bulk form or in supported form. In addition to alumina and/or silica, other suitable support/carrier materials can include, but are not limited to, zeolites, titania, silica-titania, and titania-alumina. Suitable aluminas are porous aluminas such as gamma or eta having average pore sizes from 50 to 200 Å, or 75 to 150 Å; a surface area from 100 to 300 m²/g, or 150 to 250 m²/g; and a pore volume of from 0.25 to 1.0 cm³/g, or 0.35 to 0.8 cm³/g. More generally, any convenient size, shape, and/or pore size distribution for a catalyst suitable for hydrotreatment of a distillate (including lubricant base stock) boiling range feed in a conventional manner may be used. Preferably, the support or carrier material is an amorphous support, such as a refractory oxide. Preferably, the support or carrier material can be free or substantially free of the presence of molecular sieve, where substantially free of molecular sieve is defined as having a content of molecular sieve of less than about 0.01 wt %.

The at least one Group VIII non-noble metal, in oxide form, can typically be present in an amount ranging from about 2 wt % to about 40 wt %, preferably from about 4 wt % to about 15 wt %. The at least one Group VI metal, in oxide form, can typically be present in an amount ranging from about 2 wt % to about 70 wt %, preferably for supported catalysts from about 6 wt % to about 40 wt % or from about 10 wt % to about 30 wt %. These weight percents are based on the total weight of the catalyst. Suitable metal catalysts include cobalt/molybdenum (1-10% Co as oxide, 10-40% Mo as oxide), nickel/molybdenum (1-10% Ni as oxide, 10-40% Co as oxide), or nickel/tungsten (1-10% Ni as oxide, 10-40% W as oxide) on alumina, silica, silica-alumina, or titania.

The hydrotreatment is carried out in the presence of hydrogen. A hydrogen stream is, therefore, fed or injected into a vessel or reaction zone or hydroprocessing zone in which the hydroprocessing catalyst is located. Hydrogen, which is contained in a hydrogen “treat gas,” is provided to the reaction zone. Treat gas, as referred to in this invention, can be either pure hydrogen or a hydrogen-containing gas, which is a gas stream containing hydrogen in an amount that is sufficient for the intended reaction(s), optionally including one or more other gasses (e.g., nitrogen and light hydrocarbons such as methane). The treat gas stream introduced into a reaction stage will preferably contain at least about 50 vol. % and more preferably at least about 75 vol. % hydrogen. Optionally, the hydrogen treat gas can be substantially free (less than 1 vol %) of impurities such as H₂S and NH₃ and/or such impurities can be substantially removed from a treat gas prior to use.

Hydrogen can be supplied at a rate of from about 100 SCF/B (standard cubic feet of hydrogen per barrel of feed) (17 Nm³/m³) to about 10000 SCF/B (1700 Nm³/m³). Preferably, the hydrogen is provided in a range of from about 200 SCF/B (34 Nm³/m³) to about 2500 SCF/B (420 Nm³/m³). Hydrogen can be supplied co-currently with the input feed to the hydrotreatment reactor and/or reaction zone or separately via a separate gas conduit to the hydrotreatment zone.

Hydrotreating conditions can include temperatures of 200° C. to 450° C., or 315° C. to 425° C.; pressures of 250 psig (1.8 MPag) to 5000 psig (34.6 MPag) or 300 psig (2.1 MPag) to 3000 psig (20.8 MPag); liquid hourly space velocities (LHSV) of 0.1 hr⁻¹ to 10 hr⁻¹; and hydrogen treat rates of 200 scf/B (35.6 m³/m³) to 10,000 scf/B (1781 m³/m³), or 500 (89 m³/m³) to 10,000 scf/B (1781 m³/m³).

In various aspects, the deasphalted oil can be exposed to a hydrocracking catalyst under effective hydrocracking conditions. Hydrocracking catalysts typically contain sulfided base metals on acidic supports, such as amorphous silica alumina, cracking zeolites such as USY, or acidified alumina. Often these acidic supports are mixed or bound with other metal oxides such as alumina, titania or silica. Examples of suitable acidic supports include acidic molecular sieves, such as zeolites or silicoaluminophophates. One example of suitable zeolite is USY, such as a USY zeolite with cell size of 24.30 Angstroms or less. Additionally or alternately, the catalyst can be a low acidity molecular sieve, such as a USY zeolite with a Si to Al ratio of at least about 20, and preferably at least about 40 or 50. ZSM-48, such as ZSM-48 with a SiO₂ to Al₂O₃ ratio of about 110 or less, such as about 90 or less, is another example of a potentially suitable hydrocracking catalyst. Still another option is to use a combination of USY and ZSM-48. Still other options include using one or more of zeolite Beta, ZSM-5, ZSM-35, or ZSM-23, either alone or in combination with a USY catalyst. Non-limiting examples of metals for hydrocracking catalysts include metals or combinations of metals that include at least one Group VIII metal, such as nickel, nickel-cobalt-molybdenum, cobalt-molybdenum, nickel-tungsten, nickel-molybdenum, and/or nickel-molybdenum-tungsten. Additionally or alternately, hydrocracking catalysts with noble metals can also be used. Non-limiting examples of noble metal catalysts include those based on platinum and/or palladium. Support materials which may be used for both the noble and non-noble metal catalysts can comprise a refractory oxide material such as alumina, silica, alumina-silica, kieselguhr, diatomaceous earth, magnesia, zirconia, or combinations thereof, with alumina, silica, alumina-silica being the most common (and preferred, in one embodiment).

When only one hydrogenation metal is present on a hydrocracking catalyst, the amount of that hydrogenation metal can be at least about 0.1 wt % based on the total weight of the catalyst, for example at least about 0.5 wt % or at least about 0.6 wt %. Additionally or alternately when only one hydrogenation metal is present, the amount of that hydrogenation metal can be about 5.0 wt % or less based on the total weight of the catalyst, for example about 3.5 wt % or less, about 2.5 wt % or less, about 1.5 wt % or less, about 1.0 wt % or less, about 0.9 wt % or less, about 0.75 wt % or less, or about 0.6 wt % or less. Further additionally or alternately when more than one hydrogenation metal is present, the collective amount of hydrogenation metals can be at least about 0.1 wt % based on the total weight of the catalyst, for example at least about 0.25 wt %, at least about 0.5 wt %, at least about 0.6 wt %, at least about 0.75 wt %, or at least about 1 wt %. Still further additionally or alternately when more than one hydrogenation metal is present, the collective amount of hydrogenation metals can be about 35 wt % or less based on the total weight of the catalyst, for example about 30 wt % or less, about 25 wt % or less, about 20 wt % or less, about 15 wt % or less, about 10 wt % or less, or about 5 wt % or less. In embodiments wherein the supported metal comprises a noble metal, the amount of noble metal(s) is typically less than about 2 wt %, for example less than about 1 wt %, about 0.9 wt % or less, about 0.75 wt % or less, or about 0.6 wt % or less. It is noted that hydrocracking under sour conditions is typically performed using a base metal (or metals) as the hydrogenation metal.

In various aspects, the conditions selected for hydrocracking for lubricant base stock production can depend on the desired level of conversion, the level of contaminants in the input feed to the hydrocracking stage, and potentially other factors. For example, hydrocracking conditions in a single stage, or in the first stage and/or the second stage of a multi-stage system, can be selected to achieve a desired level of conversion in the reaction system. Hydrocracking conditions can be referred to as sour conditions or sweet conditions, depending on the level of sulfur and/or nitrogen present within a feed. For example, a feed with 100 wppm or less of sulfur and 50 wppm or less of nitrogen, preferably less than 25 wppm sulfur and/or less than 10 wppm of nitrogen, represent a feed for hydrocracking under sweet conditions. In various aspects, hydrocracking can be performed on a thermally cracked resid, such as a deasphalted oil derived from a thermally cracked resid. In some aspects, such as aspects where an optional hydrotreating step is used prior to hydrocracking, the thermally cracked resid may correspond to a sweet feed. In other aspects, the thermally cracked resid may represent a feed for hydrocracking under sour conditions.

A hydrocracking process under sour conditions can be carried out at temperatures of about 550° F. (288° C.) to about 840° F. (449° C.), hydrogen partial pressures of from about 1500 psig to about 5000 psig (10.3 MPag to 34.6 MPag), liquid hourly space velocities of from 0.05 h⁻¹ to 10 h⁻¹, and hydrogen treat gas rates of from 35.6 m³/m³ to 1781 m³/m³ (200 SCF/B to 10,000 SCF/B). In other embodiments, the conditions can include temperatures in the range of about 600° F. (343° C.) to about 815° F. (435° C.), hydrogen partial pressures of from about 1500 psig to about 3000 psig (10.3 MPag-20.9 MPag), and hydrogen treat gas rates of from about 213 m³/m³ to about 1068 m³/m³ (1200 SCF/B to 6000 SCF/B). The LHSV can be from about 0.25 h⁻¹ to about 50 h⁻¹, or from about 0.5 h⁻¹ to about 20 h⁻¹, preferably from about 1.0 h⁻¹ to about 4.0 h⁻¹.

In some aspects, a portion of the hydrocracking catalyst can be contained in a second reactor stage. In such aspects, a first reaction stage of the hydroprocessing reaction system can include one or more hydrotreating and/or hydrocracking catalysts. The conditions in the first reaction stage can be suitable for reducing the sulfur and/or nitrogen content of the feedstock. A separator can then be used in between the first and second stages of the reaction system to remove gas phase sulfur and nitrogen contaminants. One option for the separator is to simply perform a gas-liquid separation to remove contaminant. Another option is to use a separator such as a flash separator that can perform a separation at a higher temperature. Such a high temperature separator can be used, for example, to separate the feed into a portion boiling below a temperature cut point, such as about 350° F. (177° C.) or about 400° F. (204° C.), and a portion boiling above the temperature cut point. In this type of separation, the naphtha boiling range portion of the effluent from the first reaction stage can also be removed, thus reducing the volume of effluent that is processed in the second or other subsequent stages. Of course, any low boiling contaminants in the effluent from the first stage would also be separated into the portion boiling below the temperature cut point. If sufficient contaminant removal is performed in the first stage, the second stage can be operated as a “sweet” or low contaminant stage.

Still another option can be to use a separator between the first and second stages of the hydroprocessing reaction system that can also perform at least a partial fractionation of the effluent from the first stage. In this type of aspect, the effluent from the first hydroprocessing stage can be separated into at least a portion boiling below the distillate (such as diesel) fuel range, a portion boiling in the distillate fuel range, and a portion boiling above the distillate fuel range. The distillate fuel range can be defined based on a conventional diesel boiling range, such as having a lower end cut point temperature of at least about 350° F. (177° C.) or at least about 400° F. (204° C.) to having an upper end cut point temperature of about 700° F. (371° C.) or less or 650° F. (343° C.) or less. Optionally, the distillate fuel range can be extended to include additional kerosene, such as by selecting a lower end cut point temperature of at least about 300° F. (149° C.).

In aspects where the inter-stage separator is also used to produce a distillate fuel fraction, the portion boiling below the distillate fuel fraction includes, naphtha boiling range molecules, light ends, and contaminants such as H₂S. These different products can be separated from each other in any convenient manner. Similarly, one or more distillate fuel fractions can be formed, if desired, from the distillate boiling range fraction. The portion boiling above the distillate fuel range represents the potential lubricant base stocks. In such aspects, the portion boiling above the distillate fuel range is subjected to further hydroprocessing in a second hydroprocessing stage.

A hydrocracking process under sweet conditions can be performed under conditions similar to those used for a sour hydrocracking process, or the conditions can be different. In an embodiment, the conditions in a sweet hydrocracking stage can have less severe conditions than a hydrocracking process in a sour stage. Suitable hydrocracking conditions for a non-sour stage can include, but are not limited to, conditions similar to a first or sour stage. Suitable hydrocracking conditions can include temperatures of about 500° F. (260° C.) to about 840° F. (449° C.), hydrogen partial pressures of from about 1500 psig to about 5000 psig (10.3 MPag to 34.6 MPag), liquid hourly space velocities of from 0.05 h⁻¹ to 10 h⁻¹, and hydrogen treat gas rates of from 35.6 m³/m³ to 1781 m³/m³ (200 SCF/B to 10,000 SCF/B). In other embodiments, the conditions can include temperatures in the range of about 600° F. (343° C.) to about 815° F. (435° C.), hydrogen partial pressures of from about 1500 psig to about 3000 psig (10.3 MPag-20.9 MPag), and hydrogen treat gas rates of from about 213 m³/m³ to about 1068 m³/m³ (1200 SCF/B to 6000 SCF/B). The LHSV can be from about 0.25 to about 50 h⁻¹, or from about 0.5 h⁻¹ to about 20 h⁻¹, preferably from about 1.0 to about 4.0 h⁻¹.

In still another aspect, the same conditions can be used for hydrotreating and hydrocracking beds or stages, such as using hydrotreating conditions for both or using hydrocracking conditions for both. In yet another embodiment, the pressure for the hydrotreating and hydrocracking beds or stages can be the same.

In yet another aspect, a hydroprocessing reaction system may include more than one hydrocracking stage. If multiple hydrocracking stages are present, at least one hydrocracking stage can have effective hydrocracking conditions as described above, including a hydrogen partial pressure of at least about 1500 psig (10.3 MPag). In such an aspect, other hydrocracking processes can be performed under conditions that may include lower hydrogen partial pressures. Suitable hydrocracking conditions for an additional hydrocracking stage can include, but are not limited to, temperatures of about 500° F. (260° C.) to about 840° F. (449° C.), hydrogen partial pressures of from about 250 psig to about 5000 psig (1.8 MPag to 34.6 MPag), liquid hourly space velocities of from 0.05 to 10 h⁻¹, and hydrogen treat gas rates of from 35.6 m³/m³ to 1781 m³/m³ (200 SCF/B to 10,000 SCF/B). In other embodiments, the conditions for an additional hydrocracking stage can include temperatures in the range of about 600° F. (343° C.) to about 815° F. (435° C.), hydrogen partial pressures of from about 500 psig to about 3000 psig (3.5 MPag-20.9 MPag), and hydrogen treat gas rates of from about 213 m³/m³ to about 1068 m³/m³ (1200 SCF/B to 6000 SCF/B). The LHSV can be from about 0.25 to about 50 h⁻¹, or from about 0.5 h⁻¹ to about 20 h⁻¹, and preferably from about 1.0 h⁻¹ to about 4.0 h⁻¹.

Hydroprocessed Effluent—Solvent Dewaxing to Form Group I Bright Stock

The hydroprocessed deasphalted oil (optionally including hydroprocessed vacuum gas oil) can be separated to form one or more fuel boiling range fractions (such as naphtha or distillate fuel boiling range fractions) and at least one lubricant base stock boiling range fraction. The lubricant base stock boiling range fraction(s) can then be solvent dewaxed to produce a lubricant base stock product with a reduced (or eliminated) tendency to form haze. Lubricant base stocks (including bright stock) formed by hydroprocessing a deasphalted oil and then solvent dewaxing the hydroprocessed effluent can tend to be Group I base stocks due to having an aromatics content of at least 10 wt %.

Solvent dewaxing typically involves mixing a feed with chilled dewaxing solvent to form an oil-solvent solution. Precipitated wax is thereafter separated by, for example, filtration. The temperature and solvent are selected so that the oil is dissolved by the chilled solvent while the wax is precipitated.

An example of a suitable solvent dewaxing process involves the use of a cooling tower where solvent is prechilled and added incrementally at several points along the height of the cooling tower. The oil-solvent mixture is agitated during the chilling step to permit substantially instantaneous mixing of the prechilled solvent with the oil. The prechilled solvent is added incrementally along the length of the cooling tower so as to maintain an average chilling rate at or below 10° F. per minute, usually between about 1 to about 5° F. per minute. The final temperature of the oil-solvent/precipitated wax mixture in the cooling tower will usually be between 0 and 50° F. (−17.8 to 10° C.). The mixture may then be sent to a scraped surface chiller to separate precipitated wax from the mixture.

Representative dewaxing solvents are aliphatic ketones having 3-6 carbon atoms such as methyl ethyl ketone and methyl isobutyl ketone, low molecular weight hydrocarbons such as propane and butane, and mixtures thereof. The solvents may be mixed with other solvents such as benzene, toluene or xylene.

In general, the amount of solvent added will be sufficient to provide a liquid/solid weight ratio between the range of 5/1 and 20/1 at the dewaxing temperature and a solvent/oil volume ratio between 1.5/1 to 5/1. The solvent dewaxed oil can be dewaxed to a pour point of −6° C. or less, or −10° C. or less, or −15° C. or less, depending on the nature of the target lubricant base stock product. Additionally or alternately, the solvent dewaxed oil can be dewaxed to a cloud point of −2° C. or less, or −5° C. or less, or −10° C. or less, depending on the nature of the target lubricant base stock product. The resulting solvent dewaxed oil can be suitable for use in forming one or more types of Group I base stocks. Preferably, a bright stock formed from the solvent dewaxed oil can have a cloud point below −5° C. The resulting solvent dewaxed oil can have a viscosity index of at least 90, or at least 95, or at least 100. Preferably, at least 10 wt % of the resulting solvent dewaxed oil (or at least 20 wt %, or at least 30 wt %) can correspond to a Group I bright stock having a kinematic viscosity at 100° C. of at least 15 cSt, or at least 20 cSt, or at least 25 cSt, such as up to 50 cSt or more.

In some aspects, the reduced or eliminated tendency to form haze for the lubricant base stocks formed from the solvent dewaxed oil can be demonstrated by a reduced or minimized difference between the cloud point temperature and pour point temperature for the lubricant base stocks. In various aspects, the difference between the cloud point and pour point for the resulting solvent dewaxed oil and/or for one or more lubricant base stocks, including one or more bright stocks, formed from the solvent dewaxed oil, can be 22° C. or less, or 20° C. or less, or 15° C. or less, or 10° C. or less, or 8° C. or less, or 5° C. or less. Additionally or alternately, a reduced or minimized tendency for a bright stock to form haze over time can correspond to a bright stock having a cloud point of −10° C. or less, or −8° C. or less, or −5° C. or less, or −2° C. or less.

Additional Hydroprocessing—Catalytic Dewaxing, Hydrofinishing, and Optional Hydrocracking

In some alternative aspects, at least a lubricant boiling range portion of the hydroprocessed deasphalted oil can be exposed to further hydroprocessing (including catalytic dewaxing) to form either Group I and/or Group II base stocks, including Group I and/or Group II bright stock. In some aspects, a first lubricant boiling range portion of the hydroprocessed deasphalted oil can be solvent dewaxed as described above while a second lubricant boiling range portion can be exposed to further hydroprocessing. In other aspects, only solvent dewaxing or only further hydroprocessing can be used to treat a lubricant boiling range portion of the hydroprocessed deasphalted oil.

Optionally, the further hydroprocessing of the lubricant boiling range portion of the hydroprocessed deasphalted oil can also include exposure to hydrocracking conditions before and/or after the exposure to the catalytic dewaxing conditions. At this point in the process, the hydrocracking can be considered “sweet” hydrocracking, as the hydroprocessed deasphalted oil can have a sulfur content of 200 wppm or less.

Suitable hydrocracking conditions can include exposing the feed to a hydrocracking catalyst as previously described above. Optionally, it can be preferable to use a USY zeolite with a silica to alumina ratio of at least 30 and a unit cell size of less than 24.32 Angstroms as the zeolite for the hydrocracking catalyst, in order to improve the VI uplift from hydrocracking and/or to improve the ratio of distillate fuel yield to naphtha fuel yield in the fuels boiling range product.

Suitable hydrocracking conditions can also include temperatures of about 500° F. (260° C.) to about 840° F. (449° C.), hydrogen partial pressures of from about 1500 psig to about 5000 psig (10.3 MPag to 34.6 MPag), liquid hourly space velocities of from 0.05 h⁻¹ to 10 h⁻¹, and hydrogen treat gas rates of from 35.6 m³/m³ to 1781 m³/m³ (200 SCF/B to 10,000 SCF/B). In other embodiments, the conditions can include temperatures in the range of about 600° F. (343° C.) to about 815° F. (435° C.), hydrogen partial pressures of from about 1500 psig to about 3000 psig (10.3 MPag-20.9 MPag), and hydrogen treat gas rates of from about 213 m³/m³ to about 1068 m³/m³ (1200 SCF/B to 6000 SCF/B). The LHSV can be from about 0.25 h⁻¹ to about 50 h¹, or from about 0.5 h⁻¹ to about 20 and preferably from about 1.0 to about 4.0 h⁻¹.

For catalytic dewaxing, suitable dewaxing catalysts can include molecular sieves such as crystalline aluminosilicates (zeolites). In an embodiment, the molecular sieve can comprise, consist essentially of, or be ZSM-22, ZSM-23, ZSM-48. Optionally but preferably, molecular sieves that are selective for dewaxing by isomerization as opposed to cracking can be used, such as ZSM-48, ZSM-23, or a combination thereof. Additionally or alternately, the molecular sieve can comprise, consist essentially of, or be a 10-member ring 1-D molecular sieve, such as EU-2, EU-11, ZBM-30, ZSM-48, or ZSM-23. ZSM-48 is most preferred. Note that a zeolite having the ZSM-23 structure with a silica to alumina ratio of from about 20:1 to about 40:1 can sometimes be referred to as SSZ-32. Optionally but preferably, the dewaxing catalyst can include a binder for the molecular sieve, such as alumina, titania, silica, silica-alumina, zirconia, or a combination thereof, for example alumina and/or titania or silica and/or zirconia and/or titania.

Preferably, the dewaxing catalysts used in processes according to the invention are catalysts with a low ratio of silica to alumina. For example, for ZSM-48, the ratio of silica to alumina in the zeolite can be about 100:1 or less, such as about 90:1 or less, or about 75:1 or less, or about 70:1 or less. Additionally or alternately, the ratio of silica to alumina in the ZSM-48 can be at least about 50:1, such as at least about 60:1, or at least about 65:1.

In various embodiments, the catalysts according to the invention further include a metal hydrogenation component. The metal hydrogenation component is typically a Group VI and/or a Group VIII metal. Preferably, the metal hydrogenation component can be a combination of a non-noble Group VIII metal with a Group VI metal. Suitable combinations can include Ni, Co, or Fe with Mo or W, preferably Ni with Mo or W.

The metal hydrogenation component may be added to the catalyst in any convenient manner. One technique for adding the metal hydrogenation component is by incipient wetness. For example, after combining a zeolite and a binder, the combined zeolite and binder can be extruded into catalyst particles. These catalyst particles can then be exposed to a solution containing a suitable metal precursor. Alternatively, metal can be added to the catalyst by ion exchange, where a metal precursor is added to a mixture of zeolite (or zeolite and binder) prior to extrusion.

The amount of metal in the catalyst can be at least 0.1 wt % based on catalyst, or at least 0.5 wt %, or at least 1.0 wt %, or at least 2.5 wt %, or at least 5.0 wt %, based on catalyst. The amount of metal in the catalyst can be 20 wt % or less based on catalyst, or 10 wt % or less, or 5 wt % or less, or 2.5 wt % or less, or 1 wt % or less. For embodiments where the metal is a combination of a non-noble Group VIII metal with a Group VI metal, the combined amount of metal can be from 0.5 wt % to 20 wt %, or 1 wt % to 15 wt %, or 2.5 wt % to 10 wt %.

The dewaxing catalysts useful in processes according to the invention can also include a binder. In some embodiments, the dewaxing catalysts used in process according to the invention are formulated using a low surface area binder, a low surface area binder represents a binder with a surface area of 100 m²/g or less, or 80 m²/g or less, or 70 m²/g or less. Additionally or alternately, the binder can have a surface area of at least about 25 m²/g. The amount of zeolite in a catalyst formulated using a binder can be from about 30 wt % zeolite to 90 wt % zeolite relative to the combined weight of binder and zeolite. Preferably, the amount of zeolite is at least about 50 wt % of the combined weight of zeolite and binder, such as at least about 60 wt % or from about 65 wt % to about 80 wt %.

Without being bound by any particular theory, it is believed that use of a low surface area binder reduces the amount of binder surface area available for the hydrogenation metals supported on the catalyst. This leads to an increase in the amount of hydrogenation metals that are supported within the pores of the molecular sieve in the catalyst.

A zeolite can be combined with binder in any convenient manner. For example, a bound catalyst can be produced by starting with powders of both the zeolite and binder, combining and mulling the powders with added water to form a mixture, and then extruding the mixture to produce a bound catalyst of a desired size. Extrusion aids can also be used to modify the extrusion flow properties of the zeolite and binder mixture. The amount of framework alumina in the catalyst may range from 0.1 to 3.33 wt %, or 0.1 to 2.7 wt %, or 0.2 to 2 wt %, or 0.3 to 1 wt %.

Effective conditions for catalytic dewaxing of a feedstock in the presence of a dewaxing catalyst can include a temperature of from 280° C. to 450° C., preferably 343° C. to 435° C., a hydrogen partial pressure of from 3.5 MPag to 34.6 MPag (500 psig to 5000 psig), preferably 4.8 MPag to 20.8 MPag, and a hydrogen circulation rate of from 178 m³/m³ (1000 SCF/B) to 1781 m³/m³ (10,000 scf/B), preferably 213 m³/m³ (1200 SCF/B) to 1068 m³/m³ (6000 SCF/B). The LHSV can be from about 0.2 h⁻¹ to about 10 h⁻¹, such as from about 0.5 h⁻¹ to about 5 and/or from about 1 to about 4 h⁻¹.

Before and/or after catalytic dewaxing, the hydroprocessed deasphalted oil (i.e., at least a lubricant boiling range portion thereof) can optionally be exposed to an aromatic saturation catalyst, which can alternatively be referred to as a hydrofinishing catalyst. Exposure to the aromatic saturation catalyst can occur either before or after fractionation. If aromatic saturation occurs after fractionation, the aromatic saturation can be performed on one or more portions of the fractionated product. Alternatively, the entire effluent from the last hydrocracking or dewaxing process can be hydrofinished and/or undergo aromatic saturation.

Hydrofinishing and/or aromatic saturation catalysts can include catalysts containing Group VI metals, Group VIII metals, and mixtures thereof. In an embodiment, preferred metals include at least one metal sulfide having a strong hydrogenation function. In another embodiment, the hydrofinishing catalyst can include a Group VIII noble metal, such as Pt, Pd, or a combination thereof. The mixture of metals may also be present as bulk metal catalysts wherein the amount of metal is about 30 wt. % or greater based on catalyst. For supported hydrotreating catalysts, suitable metal oxide supports include low acidic oxides such as silica, alumina, silica-aluminas or titania, preferably alumina. The preferred hydrofinishing catalysts for aromatic saturation will comprise at least one metal having relatively strong hydrogenation function on a porous support. Typical support materials include amorphous or crystalline oxide materials such as alumina, silica, and silica-alumina. The support materials may also be modified, such as by halogenation, or in particular fluorination. The metal content of the catalyst is often as high as about 20 weight percent for non-noble metals. In an embodiment, a preferred hydrofinishing catalyst can include a crystalline material belonging to the M41S class or family of catalysts. The M41S family of catalysts are mesoporous materials having high silica content. Examples include MCM-41, MCM-48 and MCM-50. A preferred member of this class is MCM-41.

Hydrofinishing conditions can include temperatures from about 125° C. to about 425° C., preferably about 180° C. to about 280° C., a hydrogen partial pressure from about 500 psig (3.4 MPa) to about 3000 psig (20.7 MPa), preferably about 1500 psig (10.3 MPa) to about 2500 psig (17.2 MPa), and liquid hourly space velocity from about 0.1 hr⁻¹ to about 5 hr⁻¹ LHSV, preferably about 0.5 hr⁻¹ to about 1.5 hr⁻¹. Additionally, a hydrogen treat gas rate of from 35.6 m³/m³ to 1781 m³/m³ (200 SCF/B to 10,000 SCF/B) can be used.

Solvent Processing of Catalytically Dewaxed Effluent or Input Flow to Catalytic Dewaxing

For deasphalted oils derived from propane deasphalting, the further hydroprocessing (including catalytic dewaxing) can be sufficient to form lubricant base stocks with low haze formation and unexpected compositional properties. For deasphalted oils derived from C₄₊ deasphalting, after the further hydroprocessing (including catalytic dewaxing), the resulting catalytically dewaxed effluent can be solvent processed to form one or more lubricant base stock products with a reduced or eliminated tendency to form haze. The type of solvent processing can be dependent on the nature of the initial hydroprocessing (hydrotreatment and/or hydrocracking) and the nature of the further hydroprocessing (including dewaxing).

In aspects where the initial hydroprocessing is less severe, corresponding to 10 wt % to 40 wt % conversion relative to ˜700° F. (370° C.), the subsequent solvent processing can correspond to solvent dewaxing. The solvent dewaxing can be performed in a manner similar to the solvent dewaxing described above. However, this solvent dewaxing can be used to produce a Group II lubricant base stock. In some aspects, when the initial hydroprocessing corresponds to 10 wt % to 40 wt % conversion relative to 370° C., the catalytic dewaxing during further hydroprocessing can also be performed at lower severity, so that at least 6 wt % wax remains in the catalytically dewaxed effluent, or at least 8 wt %, or at least 10 wt %, or at least 12 wt %, or at least 15 wt %, such as up to 20 wt %. The solvent dewaxing can then be used to reduce the wax content in the catalytically dewaxed effluent by 2 wt % to 10 wt %. This can produce a solvent dewaxed oil product having a wax content of 0.1 wt % to 12 wt %, or 0.1 wt % to 10 wt %, or 0.1 wt % to 8 wt %, or 0.1 wt % to 6 wt %, or 1 wt % to 12 wt %, or 1 wt % to 10 wt %, or 1 wt % to 8 wt %, or 4 wt % to 12 wt %, or 4 wt % to 10 wt %, or 4 wt % to 8 wt %, or 6 wt % to 12 wt %, or 6 wt % to 10 wt %. In particular, the solvent dewaxed oil can have a wax content of 0.1 wt % to 12 wt %, or 0.1 wt % to 6 wt %, or 1 wt % to 10 wt %, or 4 wt % to 12 wt %.

In other aspects, the subsequent solvent processing can correspond to solvent extraction. Solvent extraction can be used to reduce the aromatics content and/or the amount of polar molecules. The solvent extraction process selectively dissolves aromatic components to form an aromatics-rich extract phase while leaving the more paraffinic components in an aromatics-poor raffinate phase. Naphthenes are distributed between the extract and raffinate phases. Typical solvents for solvent extraction include phenol, furfural and N-methyl pyrrolidone. By controlling the solvent to oil ratio, extraction temperature and method of contacting distillate to be extracted with solvent, one can control the degree of separation between the extract and raffinate phases. Any convenient type of liquid-liquid extractor can be used, such as a counter-current liquid-liquid extractor. Depending on the initial concentration of aromatics in the deasphalted oil, the raffinate phase can have an aromatics content of 5 wt % to 25 wt %. For typical feeds, the aromatics contents can be at least 10 wt %.

Optionally, the raffinate from the solvent extraction can be under-extracted. In such aspects, the extraction is carried out under conditions such that the raffinate yield is maximized while still removing most of the lowest quality molecules from the feed. Raffinate yield may be maximized by controlling extraction conditions, for example, by lowering the solvent to oil treat ratio and/or decreasing the extraction temperature. In various aspects, the raffinate yield from solvent extraction can be at least 40 wt %, or at least 50 wt %, or at least 60 wt %, or at least 70 wt %.

The solvent processed oil (solvent dewaxed or solvent extracted) can have a pour point of −6° C. or less, or −10° C. or less, or −15° C. or less, or −20° C. or less, depending on the nature of the target lubricant base stock product. Additionally or alternately, the solvent processed oil (solvent dewaxed or solvent extracted) can have a cloud point of −2° C. or less, or −5° C. or less, or −10° C. or less, depending on the nature of the target lubricant base stock product. Pour points and cloud points can be determined according to ASTM D97 and ASTM D2500, respectively. The resulting solvent processed oil can be suitable for use in forming one or more types of Group II base stocks. The resulting solvent dewaxed oil can have a viscosity index of at least 80, or at least 90, or at least 95, or at least 100, or at least 110, or at least 120. Viscosity index can be determined according to ASTM D2270. Preferably, at least 10 wt % of the resulting solvent processed oil (or at least 20 wt %, or at least 30 wt %) can correspond to a Group II base stock having a kinematic viscosity at 100° C. of 6 cSt to 20 cSt, or 6 cSt to 16 cSt, or 6 cSt to 14 cSt, or 6 cSt to 12 cSt, or 8 cSt to 20 cSt, or 8 cSt to 16 cSt, or 8 cSt to 14 cSt, or 8 cSt to 12 cSt, or 10 cSt to 20 cSt, or 10 cSt to 16 cSt, or 10 cSt to 14 cSt Kinematic viscosity can be determined according to ASTM D445. Additionally or alternately, the resulting base stock can have a turbidity of at least 1.5 (in combination with a cloud point of less than 0° C.), or can have a turbidity of at least 2.0, and/or can have a turbidity of 4.0 or less, or 3.5 or less, or 3.0 or less. In particular, the turbidity can be 1.5 to 4.0, or 1.5 to 3.0, or 2.0 to 4.0, or 2.0 to 3.5.

Group II Base Stock Products

For deasphalted oils derived from propane, butane, pentane, hexane and higher or mixtures thereof, the further hydroprocessing (including catalytic dewaxing) and potentially solvent processing can be sufficient to form lubricant base stocks with low haze formation (or no haze formation) and novel compositional properties. Traditional products manufactured today with kinematic viscosity of about 32 cSt at 100° C. contain aromatics that are >10% and/or sulfur that is >0.03% of the base oil.

In various aspects, base stocks produced according to methods described herein can have a kinematic viscosity of at least 14 cSt, or at least 20 cSt, or at least 25 cSt, or at least 30 cSt, or at least 32 cSt at 100° C. and can contain less than 10 wt % aromatics/greater than 90 wt % saturates and less than 0.03% sulfur. Optionally, the saturates content can be still higher, such as greater than 95 wt %, or greater than 97 wt %. In addition, detailed characterization of the branchiness (branching) of the molecules by C-NMR reveals a high degree of branch points as described further below in the examples. This can be quantified by examining the absolute number of methyl branches, or ethyl branches, or propyl branches individually or as combinations thereof. This can also be quantified by looking at the ratio of branch points (methyl, ethyl, or propyl) compared to the number of internal carbons, labeled as epsilon carbons by C-NMR. This quantification of branching can be used to determine whether a base stock will be stable against haze formation over time. For ¹³C-NMR results reported herein, samples were prepared to be 25-30 wt % in CDCl₃ with 7% Chromium (III)-acetylacetonate added as a relaxation agent. ¹³C NMR experiments were performed on a JEOL ECS NMR spectrometer for which the proton resonance frequency is 400 MHz. Quantitative ¹³C NMR experiments were performed at 27° C. using an inverse gated decoupling experiment with a 45° flip angle, 6.6 seconds between pulses, 64 K data points and 2400 scans. All spectra were referenced to TMS at 0 ppm. Spectra were processed with 0.2-1 Hz of line broadening and baseline correction was applied prior to manual integration. The entire spectrum was integrated to determine the mole % of the different integrated areas as follows: 170-190 PPM (aromatic C); 30-29.5 PPM (epsilon carbons); 15-14.5 PPM (terminal and pendant propyl groups) 14.5-14 PPM—Methyl at the end of a long chain (alpha); 12-10 PPM (pendant and terminal ethyl groups). Total methyl content was obtained from proton NMR. The methyl signal at 0-1.1 PPM was integrated. The entire spectrum was integrated to determine the mole % of methyls. Average carbon numbers obtained from gas chromatography were used to convert mole % methyls to total methyls.

Also unexpected in the composition is the discovery using Fourier Transform Ion Cyclotron Resonance—Mass Spectrometry (FTICR-MS) and/or Field Desorption Mass Spectrometry (FDMS) that the prevalence of smaller naphthenic ring structures below 6 or below 7 or below 8 naphthene rings can be similar but the residual numbers of larger naphthenic rings structures with 7 or more rings or 8+ rings or 9+ rings or 10+ rings is diminished in base stocks that are stable against haze formation.

For FTICR-MS results reported herein, the results were generated according to the method described in U.S. Pat. No. 9,418,828. The method described in U.S. Pat. No. 9,418,828 generally involves using laser desorption with Ag ion complexation (LDI-Ag) to ionize petroleum saturates molecules (including 538° C.+ molecules) without fragmentation of the molecular ion structure. Ultra-high resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry is applied to determine exact elemental formula of the saturates-Ag cations and corresponding abundances. The saturates fraction composition can be arranged by homologous series and molecular weights. The portion of U.S. Pat. No. 9,418,828 related to determining the content of saturate ring structures in a sample is incorporated herein by reference.

For FDMS results reported herein, Field desorption (FD) is a soft ionization method in which a high-potential electric field is applied to an emitter (a filament from which tiny “whiskers” have formed) that has been coated with a diluted sample resulting in the ionization of gaseous molecules of the analyte. Mass spectra produced by FD are dominated by molecular radical cations M⁺. or in some cases protonated molecular ions [M+H]⁺. Because FDMS cannot distinguish between molecules with ‘n’ naphthene rings and molecules with ‘n+7’ rings, the FDMS data was “corrected” by using the FTICR-MS data from the most similar sample. The FDMS correction was performed by applying the resolved ratio of “n” to “n+7” rings from the FTICR-MS to the unresolved FDMS data for that particular class of molecules. Hence, the FDMS data is shown as “corrected” in the figures.

Base oils of the compositions described above have further been found to provide the advantage of being haze free upon initial production and remaining haze free for extended periods of time. This is an advantage over the prior art of high saturates heavy base stocks that was unexpected.

Additionally, it has been found that these base stocks can be blended with additives to form formulated lubricants, such as but not limited to marine oils, engine oils, greases, paper machine oils, and gear oils. These additives may include, but are not restricted to, detergents, dispersants, antioxidants, viscosity modifiers, and pour point depressants. More generally, a formulated lubricating including a base stock produced from a deasphalted oil may additionally contain one or more of the other commonly used lubricating oil performance additives including but not limited to antiwear agents, dispersants, other detergents, corrosion inhibitors, rust inhibitors, metal deactivators, extreme pressure additives, anti-seizure agents, wax modifiers, viscosity index improvers, viscosity modifiers, fluid-loss additives, seal compatibility agents, friction modifiers, lubricity agents, anti-staining agents, chromophoric agents, defoamants, demulsifiers, emulsifiers, densifiers, wetting agents, gelling agents, tackiness agents, colorants, and others. For a review of many commonly used additives, see Klamann in Lubricants and Related Products, Verlag Chemie, Deerfield Beach, Fla.; ISBN 0-89573-177-0. These additives are commonly delivered with varying amounts of diluent oil, that may range from 5 weight percent to 50 weight percent.

When so blended, the performance as measured by standard low temperature tests such as the Mini-Rotary Viscometer (MRV) and Brookfield test has been shown to be superior to formulations blended with traditional base oils.

It has also been found that the oxidation performance, when blended into industrial oils using common additives such as, but not restricted to, defoamants, pour point depressants, antioxidants, rust inhibitors, has exemplified superior oxidation performance in standard oxidation tests such as the US Steel Oxidation test compared to traditional base stocks.

Other performance parameters such as interfacial properties, deposit control, storage stability, and toxicity have also been examined and are similar to or better than traditional base oils.

In addition to being blended with additives, the base stocks described herein can also be blended with other base stocks to make a base oil. These other base stocks include solvent processed base stocks, hydroprocessed base stocks, synthetic base stocks, base stocks derived from Fisher-Tropsch processes, PAO, and naphthenic base stocks. Additionally or alternately, the other base stocks can include Group I base stocks, Group II base stocks, Group III base stocks, Group IV base stocks, and/or Group V base stocks. Additionally or alternately, still other types of base stocks for blending can include hydrocarbyl aromatics, alkylated aromatics, esters (including synthetic and/or renewable esters), and or other non-conventional or unconventional base stocks. These base oil blends of the inventive base stock and other base stocks can also be combined with additives, such as those mentioned above, to make formulated lubricants.

CONFIGURATION EXAMPLES

FIG. 1 schematically shows a first configuration for processing of a deasphalted oil feed 110. Optionally, deasphalted oil feed 110 can include a vacuum gas oil boiling range portion. In FIG. 1, a deasphalted oil feed 110 is exposed to hydrotreating and/or hydrocracking catalyst in a first hydroprocessing stage 120. The hydroprocessed effluent from first hydroprocessing stage 120 can be separated into one or more fuels fractions 127 and a 370° C.+ fraction 125. The 370° C.+ fraction 125 can be solvent dewaxed 130 to form one or more lubricant base stock products, such as one or more light neutral or heavy neutral base stock products 132 and a bright stock product 134.

FIG. 2 schematically shows a second configuration for processing a deasphalted oil feed 110. In FIG. 2, solvent dewaxing stage 130 is optional. The effluent from first hydroprocessing stage 120 can be separated to form at least one or more fuels fractions 127, a first 370° C.+ portion 245, and a second optional 370° C.+ portion 225 that can be used as the input for optional solvent dewaxing stage 130. The first 370° C.+ portion 245 can be used as an input for a second hydroprocessing stage 250. The second hydroprocessing stage can correspond to a sweet hydroprocessing stage for performing catalytic dewaxing, aromatic saturation, and optionally further performing hydrocracking. In FIG. 2, at least a portion 253 of the catalytically dewaxed output 255 from second hydroprocessing stage 250 can be solvent dewaxed 260 to form at least a solvent processed lubricant boiling range product 265 that has a T10 boiling point of at least 510° C. and that corresponds to a Group II bright stock.

FIG. 3 schematically shows another configuration for producing a Group II bright stock. In FIG. 3, at least a portion 353 of the catalytically dewaxed output 355 from the second hydroprocessing stage 250 is solvent extracted 370 to form at least a processed lubricant boiling range product 375 that has a T10 boiling point of at least 510° C. and that corresponds to a Group II bright stock.

FIG. 6 schematically shows yet another configuration for producing a Group II bright stock. In FIG. 6, a vacuum resid feed 675 and a deasphalting solvent 676 is passed into a deasphalting unit 680. In some aspects, deasphalting unit 680 can perform propane deasphalting, but in other aspects a C₄₊ solvent can be used. Deasphalting unit 680 can produce a rock or asphalt fraction 682 and a deasphalted oil 610. Optionally, deasphalted oil 610 can be combined with another vacuum gas oil boiling range feed 671 prior to being introduced into first (sour) hydroprocessing stage 620. A lower boiling portion 627 of the effluent from hydroprocessing stage 620 can be separated out for further use and/or processing as one or more naphtha fractions and/or distillate fractions. A higher boiling portion 625 of the hydroprocessing effluent can be a) passed into a second (sweet) hydroprocessing stage 650 and/or b) withdrawn 626 from the processing system for use as a fuel, such as a fuel oil or fuel oil blendstock. Second hydroprocessing stage 650 can produce an effluent that can be separated to form one or more fuels fractions 657 and one or more lubricant base stock fractions 655, such as one or more bright stock fractions.

FIGS. 11 to 13 show examples of using blocked operation and/or partial product recycle during lubricant production based on a feed including deasphalted resid. In FIGS. 11 to 13, after initial sour stage processing, the hydroprocessed effluent is fractionated to form light neutral, heavy neutral, and brightstock portions. FIG. 11 shows an example of the process flow during processing to form light neutral base stock. FIG. 12 shows an example of the process flow during processing to form heavy neutral base stock. FIG. 13 shows an example of the process flow during processing to form brightstock.

In FIG. 11, a feed 705 is introduced into a deasphalter 710. The deasphalter 710 generates a deasphalted oil 715 and deasphalter rock or residue 718. The deasphalted oil 715 is then processed in a sour processing stage 720. Optionally, a portion 771 of recycled light neutral base product 762 can be combined with deasphalted oil 715. Sour processing stage 720 can include one or more of a deasphalting catalyst, a hydrotreating catalyst, a hydrocracking catalyst, and/or an aromatic saturation catalyst. The conditions in sour processing stage 720 can be selected to at least reduce the sulfur content of the hydroprocessed effluent 725 to 20 wppm or less. This can correspond to 15 wt % to 40 wt % conversion of the feed relative to 370° C. Optionally, the amount of conversion in the sour processing stage 720 can be any convenient higher amount so long as the combined conversion in sour processing stage 720 and sweet processing stage 750 is 90 wt % or less.

The hydroprocessed effluent 725 can then be passed into fractionation stage 730 for separation into a plurality of fractions. In the example shown in FIG. 11, the hydroprocessed effluent is separated into a light neutral portion 732, a heavy neutral portion 734, and a brightstock portion 736. To allow for blocked operation, the light neutral portion 732 can be sent to corresponding light neutral storage 742, the heavy neutral portion 734 can be sent to corresponding heavy neutral storage 744, and the brightstock portion 736 can be sent to corresponding brightstock storage 746. A lower boiling range fraction 731 corresponding to fuels and/or light ends can also be generated by fractionation stage 730. Optionally, fractionation stage can generate a plurality of lower boiling range fractions 731.

FIG. 11 shows an example of the processing system during a light neutral processing block. In FIG. 11, the feed 752 to sweet processing stage 750 corresponds to a feed derived from light neutral storage 742. The sweet processing stage 750 can include at least dewaxing catalyst, and optionally can further include one or more of hydrocracking catalyst and aromatics saturation catalyst. The dewaxed effluent 755 from sweet processing stage 750 can then be passed into a fractionator 760 to form light neutral base stock product 762. A lower boiling fraction 761 corresponding to fuels and/or light ends can also be separated out by fractionator 760. Optionally, a portion of light neutral base stock 762 can be recycled. The recycled portion of light neutral base stock 762 can be used as a recycled feed portion 771 and/or as a recycled portion 772 that is added to light neutral storage 742. Recycling a portion 771 for use as part of the feed can be beneficial for increasing the lifetime of the catalysts in sour processing stage 720. Recycling a portion 772 to light neutral storage 742 can be beneficial for increasing conversion and/or VI.

FIG. 12 shows the same processing configuration during processing of a heavy neutral block. In FIG. 12, the feed 754 to sweet processing stage 750 is derived from heavy neutral storage 744. The dewaxed effluent 755 from sweet processing stage 750 can be fractionated 760 to form lower boiling portion 761, heavy neutral base stock product 764, and light neutral base stock product 762. Because block operation to form a heavy neutral base stock results in production of both a light neutral product 762 and a heavy neutral product 764, various optional recycle streams can also be used. In the example shown in FIG. 12, optional recycle portions 771 and 772 can be used for recycle of the light neutral product 762. Additionally, optional recycle portions 781 and 784 can be used for recycle of the heavy neutral product 764. Recycle portions 781 and 784 can provide similar benefits to those for recycle portions 771 and/or 772.

FIG. 13 shows the same processing configuration during processing of a bright stock block. In FIG. 13, the feed 756 to sweet processing stage 750 is derived from bright stock storage 746. The dewaxed effluent 755 from sweet processing stage 750 can be fractionated 760 to form lower boiling portion 761, bottoms product 766, heavy neutral base stock product 764, and light neutral base stock product 762. Bottoms product 766 can then be extracted 790 to form a bright stock product 768. The aromatic extract 793 produced in extractor 790 can be recycled for use, for example, as part of the feed to deasphalter 710.

Because block operation to form a bright stock results in production of a bright stock product 768 as well as a light neutral product 762 and a heavy neutral product 764, various optional recycle streams can also be used. In the example shown in FIG. 9, optional recycle portions 771 and 772 can be used for recycle of the light neutral product 762, while optional recycle portions 781 and 784 can be used for recycle of the heavy neutral product 764. Additionally, optional recycle portions 791 and 796 can be used for recycle of the bottoms product 766. Recycle portions 791 and 796 can provide similar benefits to those for recycle portions 771, 772, 781, and/or 784.

Example 1

A deasphalted oil and vacuum gas oil mixture shown in Table B was processed in a configuration similar to FIG. 3.

TABLE 1 Pentane deasphalted oil (65%) and vacuum gas oil (35%) properties API Gravity 13.7 Sulfur (wt %) 3.6 Nitrogen (wppm) 2099 Ni (wppm) 5.2 V (wppm) 14.0 CCR (wt %) 8.1 Wax (wt %) 4.2 GCD Distillation (wt %) (° C.)  5% 422 10% 465 30% 541 50% 584 70% n/a 90% 652

The deasphalted oil in Table 1 was processed at 0.2 hr⁻¹ LHSV, a treat gas rate of 8000 scf/b, and a pressure of 2250 psig over a catalyst fill of 50 vol % demetalization catalyst, 42.5 vol % hydrotreating catalyst, and 7.5% hydrocracking catalyst by volume. The demetallization catalyst was a commercially available large pore supported demetallization catalyst. The hydrotreating catalyst was a stacked bed of commercially available supported NiMo hydrotreating catalyst and commercially available bulk NiMo catalyst. The hydrocracking catalyst was a standard distillate selective catalyst used in industry. Such catalysts typically include NiMo or NiW on a zeolite/alumina support. Such catalysts typically have less than 40 wt % zeolite of a zeolite with a unit cell size of less than 34.38 Angstroms. A preferred zeolite content can be less than 25 wt % and/or a preferred unit cell size can be less than 24.32 Angstroms. Activity for such catalysts can be related to the unit cell size of the zeolite, so the activity of the catalyst can be adjusted by selecting the amount of zeolite. The feed was exposed to the demetallization catalyst at 745° F. (396° C.) and exposed to the combination of the hydrotreating and hydrocracking catalyst at 761° F. (405° C.) in an isothermal fashion.

The above processing conditions resulted in conversion relative to 510° C. of 73.9 wt % and conversion relative to 370° C. of 50 wt %. The hydroprocessed effluent was separated to remove fuels boiling range portions from a 370° C.+ portion. The resulting 370° C.+ portion was then further hydroprocessed. The further hydroprocessing included exposing the 370° C.+ portion to a 0.6 wt % Pt on ZSM-48 dewaxing catalyst (70:1 silica to alumina ratio, 65 wt % zeolite to 35 wt % binder) followed by a 0.3 wt % Pt/0.9 wt % Pd on MCM-41 aromatic saturation catalyst (65% zeolite to 35 wt % binder). The operating conditions included a hydrogen pressure of 2400 psig, a treat gas rate of 5000 scf/b, a dewaxing temperature of 658° F. (348° C.), a dewaxing catalyst space velocity of 1.0 hr⁻¹, an aromatic saturation temperature of 460° F. (238° C.), and an aromatic saturation catalyst space velocity of 1.0 hr⁻¹. The properties of the 560° C.+ portion of the catalytically dewaxed effluent are shown in Table 2. Properties for a raffinate fraction and an extract fraction derived from the catalytically dewaxed effluent are also shown.

TABLE 2 Catalytically dewaxed effluent 560° C.+ Raffinate Product Fraction CDW effluent (yield 92.2%) Extract API 30.0 30.2 27.6 VI 104.2 105.2 89 KV @100° C. 29.8 30.3 29.9 KV @40° C. 401 405 412 Pour Pt (° C.) −21 −30 Cloud Pt (° C.) 7.8 −24

Although the catalytically dewaxed effluent product was initially clear, haze developed within 2 days. Solvent dewaxing of the catalytically dewaxed effluent product in Table 2 did not reduce the cloud point significantly (cloud after solvent dewaxing of 6.5° C.) and removed only about 1 wt % of wax, due in part to the severity of the prior catalytic dewaxing. However, extracting the catalytically dewaxed product shown in Table 9 with N-methyl pyrrolidone (NMP) at a solvent/water ratio of 1 and at a temperature of 100° C. resulted in a clear and bright product with a cloud point of −24° C. that appeared to be stable against haze formation. The extraction also reduced the aromatics content of the catalytically dewaxed product from about 2 wt % aromatics to about 1 wt % aromatics. This included reducing the 3-ring aromatics content of the catalytically dewaxed effluent (initially about 0.2 wt %) by about 80%. This result indicates a potential relationship between waxy haze formation and the presence of polynuclear aromatics in a bright stock.

Example 2

A feed similar to Example 1 was processed in a configuration similar to FIG. 2, with various processing conditions were modified. The initial hydroprocessing severity was reduced relative to the conditions in Example 1 so that the initial hydroprocessing conversion was 59 wt % relative to 510° C. and 34.5 wt % relative to 370° C. These lower conversions were achieved by operating the demetallization catalyst at 739° F. (393° C.) and the hydrotreating/hydrocracking catalyst combination at 756° F. (402° C.).

The hydroprocessed effluent was separated to separate fuels boiling range fraction(s) from the 370° C.+ portion of the hydroprocessed effluent. The 370° C.+ portion was then treated in a second hydroprocessing stage over a hydrocracking catalyst and a dewaxing catalyst. Additionally, a small amount of a hydrotreating catalyst (hydrotreating catalyst LHSV of 10 hr⁻¹) was included prior to the hydrocracking catalyst, and the feed was exposed to the hydrotreating catalyst under substantially the same conditions as the hydrocracking catalyst. The reaction conditions included a hydrogen pressure of 2400 psig and a treat gas rate of 5000 scf/b. In a first run, the second hydroprocessing conditions were selected to under dewax the hydroprocessed effluent. The under-dewaxing conditions corresponded to a hydrocracking temperature of 675° F. (357° C.), a hydrocracking catalyst LHSV of 1.2 hr⁻¹, a dewaxing temperature of 615° F. (324° C.), a dewaxing catalyst LHSV of 1.2 hr⁻¹, an aromatic saturation temperature of 460° F. (238° C.), and an aromatic saturation catalyst LHSV of 1.2 hr⁻¹. In a second run, the second hydroprocessing conditions were selected to more severely dewax the hydroprocessed effluent. The higher severity dewaxing conditions corresponded to a hydrocracking temperature of 675° F. (357° C.), a hydrocracking catalyst LHSV of 1.2 hr⁻¹, a dewaxing temperature of 645° F. (340° C.), a dewaxing catalyst LHSV of 1.2 hr⁻¹, an aromatic saturation temperature of 460° F. (238° C.), and an aromatic saturation catalyst LHSV of 1.2 hr⁻¹. The 510° C.+ portions of the catalytically dewaxed effluent are shown in Table 3.

TABLE 3 Catalytically dewaxed effluents Product Fraction Under-dewaxed Higher severity VI 106.6 106.4 KV @100° C. 37.6 30.5 KV @40° C. 551 396 Pour Pt (° C.) −24 −24 Cloud Pt (° C.) 8.6 4.9

Both samples in Table 3 were initially bright and clear, but a haze developed in both samples within one week. Both samples were solvent dewaxed. This reduced the wax content of the under-dewaxed sample to 6.8 wt % and the wax content of the higher severity dewaxing sample to 1.1 wt %. The higher severity dewaxing sample still showed a slight haze. However, the under-dewaxed sample, after solvent dewaxing, had a cloud point of −21° C. and appeared to be stable against haze formation.

Example 3—Viscosity and Viscosity Index Relationships

FIG. 4 shows an example of the relationship between processing severity, kinematic viscosity, and viscosity index for lubricant base stocks formed from a deasphalted oil. The data in FIG. 4 corresponds to lubricant base stocks formed form a pentane deasphalted oil at 75 wt % yield on resid feed. The deasphalted oil had a solvent dewaxed VI of 75.8 and a solvent dewaxed kinematic viscosity at 100° C. of 333.65.

In FIG. 4, kinematic viscosities (right axis) and viscosity indexes (left axis) are shown as a function of hydroprocessing severity (510° C.+ conversion) for a deasphalted oil processed in a configuration similar to FIG. 1, with the catalysts described in Example 1. As shown in FIG. 4, increasing the hydroprocessing severity can provide VI uplift so that deasphalted oil can be converted (after solvent dewaxing) to lubricant base stocks. However, increasing severity also reduces the kinematic viscosity of the 510° C.+ portion of the base stock, which can limit the yield of bright stock. The 370° C.-510° C. portion of the solvent dewaxed product can be suitable for forming light neutral and/or heavy neutral base stocks, while the 510° C.+ portion can be suitable for forming bright stocks and/or heavy neutral base stocks.

Example 4—Variations in Sweet and Sour Hydrocracking

In addition to providing a method for forming Group II base stocks from a challenged feed, the methods described herein can also be used to control the distribution of base stocks formed from a feed by varying the amount of conversion performed in sour conditions versus sweet conditions. This is illustrated by the results shown in FIG. 5.

In FIG. 5, the upper two curves show the relationship between the cut point used for forming a lubricant base stock of a desired viscosity (bottom axis) and the viscosity index of the resulting base stock (left axis). The curve corresponding to the circle data points represents processing of a C₅ deasphalted oil using a configuration similar to FIG. 2, with all of the hydrocracking occurring in the sour stage. The curve corresponding to the square data points corresponds to performing roughly half of the hydrocracking conversion in the sour stage and the remaining hydrocracking conversion in the sweet stage (along with the catalytic dewaxing). The individual data points in each of the upper curves represent the yield of each of the different base stocks relative to the amount of feed introduced into the sour processing stage. It is noted that summing the data points within each curve shows the same total yield of base stock, which reflects the fact that the same total amount of hydrocracking conversion was performed in both types of processing runs. Only the location of the hydrocracking conversion (all sour, or split between sour and sweet) was varied.

The lower pair of curves provides additional information about the same pair of process runs. As for the upper pair of curves, the circle data points in the lower pair of curves represent all hydrocracking in the sour stage and the square data points correspond to a split of hydrocracking between sour and sweet stages. The lower pair of curves shows the relationship between cut point (bottom axis) and the resulting kinematic viscosity at 100° C. (right axis). As shown by the lower pair of curves, the three cut point represent formation of a light neutral base stock (5 or 6 cSt), a heavy neutral base stock (10-12 cSt), and a bright stock (about 30 cSt). The individual data points for the lower curves also indicate the pour point of the resulting base stock.

As shown in FIG. 5, altering the conditions under which hydrocracking is performed can alter the nature of the resulting lubricant base stocks. Performing all of the hydrocracking conversion during the first (sour) hydroprocessing stage can result in higher viscosity index values for the heavy neutral base stock and bright stock products, while also producing an increased yield of heavy neutral base stock. Performing a portion of the hydrocracking under sweet conditions increased the yield of light neutral base stock and bright stock with a reduction in heavy neutral base stock yield. Performing a portion of the hydrocracking under sweet conditions also reduced the viscosity index values for the heavy neutral base stock and bright stock products. This demonstrates that the yield of base stocks and/or the resulting quality of base stocks can be altered by varying the amount of conversion performed under sour conditions versus sweet conditions.

Example 5—Blocked Operation

A configuration similar to the configuration shown in FIGS. 7 to 9 was used to process a resid-type feed that substantially included 510° C.+ components. The configuration for this example did not include recycle products as part of the feed for the sour stage or for further sweet stage processing. The feed was initially deasphalted using n-pentane to product 75 wt % deasphalted oil and 25 wt % deasphalter rock or residue. The resulting deasphalted oil had an API gravity of 12.3, a sulfur content of 3.46 wt %, and a nitrogen content of 2760 wppm. The deasphalted oil was then hydroprocessed in an initial sour hydroprocessing stage that included four catalyst beds. The first two catalyst beds corresponded to commercially available demetallization catalysts. The third catalyst bed corresponded to commercially available hydrotreating catalyst, including at least a portion of a commercially available bulk metal hydrotreating catalyst. The fourth catalyst bed included a commercially available hydrocracking catalyst. The effluent from each catalyst bed was cascaded to the next catalyst bed. The average reaction temperature across each catalyst bed was 378° C. for the first demetallization catalyst bed, 388° C. for the second demetallization catalyst bed, 389° C. for the hydrotreating catalyst bed, and 399° C. for the hydrocracking catalyst bed. The flow rate of the feed relative to the total volume of catalyst in the sour hydroprocessing stage was an LHSV of 0.16 hr⁻¹. The hydrogen partial pressure was 2500 psia (17.2 MPa-a) and the hydrogen treat gas flow rate was 8000 scf/b (˜1420 Nm³/m³). Under these conditions, the hydroprocessing consumed roughly 2300 scf/b (˜400 Nm³/m³). The conditions resulted in roughly 50 wt % conversion relative to 370° C.

After processing in the initial sour stage, a fractionator was used to separate the hydroprocessed effluent into various fractions. The fractions included light ends, at least one fuels fraction, a light neutral fraction, a heavy neutral fraction, and a brightstock fraction. Table 4 shows additional details regarding the hydroprocessed effluent from the initial sour stage.

TABLE 4 Hydroprocessed Effluent (Sour Stage) Wt % (of total Nitrogen content Solvent Product effluent) (wppm) dewaxed VI H₂S 3.7 NH₃ 0.3 C₁ 0.4 C₂ 0.4 C₃ 0.7 C₄ 0.9 C₅ 1.3 C₆ to 370° C. (fuels 45.6 fraction) Light Neutral 13.9 1 102.8 Heavy Neutral 14.0 1 99.8 Brightstock 22.2 5-10 110.5

The light neutral, heavy neutral, and brightstock fractions from the initial sour hydroprocessing stage were then further hydroprocessed in the presence of a noble metal hydrocracking catalyst (0.6 wt % Pt on alumina-bound USY) and a noble metal dewaxing catalyst (0.6 wt % Pt on alumina bound ZSM-48. The sweet stage conditions for each fraction were selected separately to achieve desired VI values.

For the light neutral feed, the sweet stage conditions were selected to achieve roughly 30 wt % conversion relative to 370° C. This produced a light neutral lubricant base stock in a 70.6 wt % yield relative to the light neutral feed. The resulting light neutral base stock had a VI of 109.9 and a kinematic viscosity at 100° C. of 5.8 cSt. For the heavy neutral feed, the sweet stage conditions were selected to achieve roughly 6 wt % conversion relative to 370° C. This produced a heavy neutral lubricant base stock in a 93.7 wt % yield relative to the heavy neutral feed. The resulting heavy neutral base stock had a VI of 106.6 and a kinematic viscosity at 100° C. of 11.7 cSt. For the brightstock feed, the sweet stage conditions were selected to achieve roughly 30 wt % conversion relative to 370° C. This produced a brightstock base stock in a 54.3 wt % yield relative to the brightstock feed. The resulting brightstock base stock had a VI of 103 and a kinematic viscosity at 100° C. of 32 cSt. Additionally, a yield of 16.1 wt % of a light neutral lubricant boiling range product was generated with a kinematic viscosity at 100° C. of 6 cSt and a viscosity index of roughly 100. This additional light neutral lubricant boiling range product was optionally suitable for recycle to either the light neutral or heavy neutral processing block. This could allow, for example, the light neutral or heavy neutral processing block to be operated at a reduced temperature (due to further reduced nitrogen in the combined feed). Such reduced temperature can be favorable for further reducing any additional aromatics that might be present in the recycled product. Alternatively, the additional light neutral product could be recycled to the initial sour stage for further upgrading, although this could lead to additional production of fuels as opposed to lubricant products.

Example 6—Production of Base Stocks (Including Bright Stock) at High Conversion

Another series of processing runs were performed using a C₅ DAO (75 wt % yield) as a feed for lubricant production. The configuration was similar to Example 5. Block processing was used for the sweet processing stage. The light neutral, heavy neutral, and brightstock portions were processed under conditions to produce two levels of conversion relative to 370° C. In a first set of runs, the combined sour stage and sweet stage conversion was 60 wt %. In a second set of runs, the combined sour stage and sweet stage conversion was 82 wt %. It is noted that at high rates of conversion during a single pass, any portions of a lubricant product that are recycled could potentially undergo conversion amounts of greater than 70 wt %, or greater than 75 wt %, or greater than 80 wt %, such as up to 90 wt % or more.

Conventionally, conversion of greater than roughly 70 wt % of a feedstock during lubricant product is believed to lead to large reductions in viscosity index for resulting lubricant products. Without being bound by any particular theory, this is believed to be due in part to conversion of isoparaffins with the feed at elevated levels of conversion. It has been surprisingly discovered that feeds derived from high yield deasphalted oils (such as deasphalting yields of at least 50 wt %) can be undergo greater than 70 wt % conversion without having substantial reductions in VI. This is believed to be related to the unusually high aromatic content of lubricant feeds derived from high yield deasphalted oils.

Table 5 shows results from processing the C₅ DAO feed in this example at conversion amounts of 60 wt % and 82 wt % (combined conversion across initial sour stage and second sweet stage) for production during block operation of a light neutral product, a heavy neutral product, and a brightsock product. As shown in Table 5, increasing the combined conversion results in products with comparable (or potentially higher) viscosity index values, while also allowing generating products with substantially reduced pour point values.

TABLE 5 Product properties at varying conversion 82 wt % 60 wt % combined conversion combined conversion (relative to 370° C.) (relative to 370° C.) Light Neutral VI 106 106 Pour Point (° C.) −64 −34 KV @ 100° C. (cSt) 4.9 4.3 Heavy Neutral VI 100.9 100.5 Pour Point (° C.) −48 −34 KV @ 100° C. (cSt) 11.9 12.6 Bright Stock VI 109 106.3 Pour Point (° C.) −32 −20 KV @ 100° C. (cSt) 34.6 43.2

Additional Embodiments Embodiment 1

A method for making lubricant base stock, comprising: hydroprocessing a feedstock comprising a 370° C.+ fraction under first effective hydroprocessing conditions to form a hydroprocessed effluent, the at least a portion of the deasphalted oil having an aromatics content of at least about 50 wt %, the hydroprocessed effluent comprising a sulfur content of 300 wppm or less, a nitrogen content of 100 wppm or less, or a combination thereof; separating the hydroprocessed effluent to form at least a first fraction comprising a T5 distillation point of at least 370° C. and a kinematic viscosity at 100° C. of 6 cSt to 20 cSt (or 8 cSt to 16 cSt, or 10 cSt to 14 cSt); hydroprocessing at least a portion of the first fraction under second effective hydroprocessing conditions, the second effective hydroprocessing conditions comprising catalytic dewaxing conditions, to form a catalytically dewaxed effluent comprising a 370° C.+ portion; and solvent extracting at least a portion of the 370° C.+ portion of the catalytically dewaxed effluent to form a solvent processed effluent.

Embodiment 2

A method for making lubricant base stock, comprising: performing solvent deasphalting, optionally using a C₄₊ solvent, under effective solvent deasphalting conditions on a feedstock having a T5 boiling point of at least about 370° C. (or at least about 400° C., or at least about 450° C., or at least about 500° C.), the effective solvent deasphalting conditions producing a yield of deasphalted oil of at least about 50 wt % of the feedstock; hydroprocessing at least a portion of the deasphalted oil under first effective hydroprocessing conditions to form a hydroprocessed effluent, the at least a portion of the deasphalted oil having an aromatics content of at least about 50 wt %, the hydroprocessed effluent comprising a sulfur content of 300 wppm or less, a nitrogen content of 100 wppm or less, or a combination thereof; separating the hydroprocessed effluent to form at least a first fraction comprising a T5 distillation point of at least 370° C. and a kinematic viscosity at 100° C. of 6 cSt to 20 cSt (or 8 cSt to 16 cSt, or 10 cSt to 14 cSt); hydroprocessing at least a portion of the first fraction under second effective hydroprocessing conditions, the second effective hydroprocessing conditions comprising catalytic dewaxing conditions, to form a catalytically dewaxed effluent comprising a 370° C.+ portion; and solvent extracting at least a portion of the 370° C.+ portion of the catalytically dewaxed effluent to form a solvent processed effluent.

Embodiment 3

A method for making lubricant base stock, comprising: hydroprocessing a feedstock comprising a 370° C.+ fraction under first effective hydroprocessing conditions to form a hydroprocessed effluent, the at least a portion of the deasphalted oil having an aromatics content of at least about 50 wt %, the hydroprocessed effluent comprising a sulfur content of 300 wppm or less, a nitrogen content of 100 wppm or less, or a combination thereof; separating the hydroprocessed effluent to form at least a first fraction having a T5 distillation point of at least 370° C.; hydroprocessing at least a portion of the first fraction under second effective hydroprocessing conditions, the second effective hydroprocessing conditions comprising catalytic dewaxing conditions, to form a catalytically dewaxed effluent comprising a 370° C.+ portion, the 370° C.+ portion comprising a second fraction comprising a kinematic viscosity at 100° C. of 6 cSt to 20 cSt (or 8 cSt to 16 cSt, or 10 cSt to 14 cSt); and solvent extracting at least a portion of the second fraction to form a solvent processed effluent.

Embodiment 4

A method for making lubricant base stock, comprising: performing solvent deasphalting, optionally using a C₄₊ solvent, under effective solvent deasphalting conditions on a feedstock having a T5 boiling point of at least about 370° C. (or at least about 400° C., or at least about 450° C., or at least about 500° C.), the effective solvent deasphalting conditions producing a yield of deasphalted oil of at least about 50 wt % of the feedstock; hydroprocessing at least a portion of the deasphalted oil under first effective hydroprocessing conditions to form a hydroprocessed effluent, the at least a portion of the deasphalted oil having an aromatics content of at least about 50 wt %, the hydroprocessed effluent comprising a sulfur content of 300 wppm or less, a nitrogen content of 100 wppm or less, or a combination thereof; separating the hydroprocessed effluent to form at least a first fraction comprising a T5 distillation point of at least 370° C.; hydroprocessing at least a portion of the first fraction under second effective hydroprocessing conditions, the second effective hydroprocessing conditions comprising catalytic dewaxing conditions, to form a catalytically dewaxed effluent comprising a 370° C.+ portion, the 370° C.+ portion comprising a second fraction comprising a kinematic viscosity at 100° C. of 6 cSt to 20 cSt (or 8 cSt to 16 cSt, or 10 cSt to 14 cSt); and solvent extracting at least a portion of the second fraction to form a solvent processed effluent.

Embodiment 5

The method of Embodiment 3 or 4, further comprising separating at least a portion of the catalytically dewaxed effluent to form the second fraction or separating at least a portion of the 370° C.+ portion of the catalytically dewaxed effluent to form the second fraction.

Embodiment 6

The method of any of the above embodiments, wherein the solvent processed effluent comprises a VI of at least 80 and a kinematic viscosity at 100° C. of 6 cSt to 20 cSt.

Embodiment 7

The method of any of the above embodiments, wherein the solvent processed effluent comprises a pour point of −6° C. or less (or −10° C. or less, or −15° C. or less, or −20° C. or less), a cloud point of −2° C. or less (or −5° C. or less or −10° C. or less, or −15° C. or less, or −20° C. or less), or a combination thereof.

Embodiment 8

The method of any of the above embodiments, wherein the solvent extracting comprises solvent extracting with N-methylpyrrolidone, furfural, phenol, or a combination thereof.

Embodiment 9

The method of any of Embodiments 2 or 4-8, wherein the yield of deasphalted oil is at least 55 wt %, or at least 60 wt %, or at least 65 wt %, or at least 70 wt %, or at least 75 wt %, or wherein the deasphalted oil has an aromatics content of at least 55 wt %, or at least 60 wt %, or at least 65 wt %, or at least 70 wt % based on a weight of the deasphalted oil, or a combination thereof.

Embodiment 10

The method of any of Embodiments 2 or 4-9, wherein the C₄₊ solvent comprises a C₅₊ solvent, a mixture of two or more C₅ isomers, or a combination thereof.

Embodiment 11

The method of any of the above embodiments, wherein the solvent processed effluent comprises a viscosity index of 80 to 160, or 80 to 140, or 80 to 120, or 90 to 160, or 90 to 140, or 90 to 120, or 100 to 160, or 100 to 140, or 120 to 160, or 120 to 140.

Embodiment 12

The method of any of the above embodiments, wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 226 nm of at least 0.020, or at least 0.025, or at least 0.030, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 226 nm of less than 0.020, or less than 0.018, or less than 0.016.

Embodiment 13

The method of any of the above embodiments, wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 254 nm of at least 0.010, or at least 0.012, or at least 0.014, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 254 nm of less than 0.010, or less than 0.008, or less than 0.006, or less than 0.004.

Embodiment 14

The method of any of the above embodiments, wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 275 nm of at least 0.010, or at least 0.012, or at least 0.014, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 275 nm of less than 0.010, or less than 0.008, or less than 0.006, or less than 0.004.

Embodiment 15

The method of any of the above embodiments, wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 302 nm of at least 0.020, or at least 0.025, or at least 0.030, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 302 nm of less than 0.010, or less than 0.008, or less than 0.006, or less than 0.004.

Embodiment 16

The method of any of the above embodiments, wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 310 nm of at least 0.030, or at least 0.035, or at least 0.040, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 310 nm of less than 0.010, or less than 0.008, or less than 0.006, or less than 0.004.

Embodiment 17

The method of any of the above embodiments, wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 325 nm of at least 0.010, or at least 0.012, or at least 0.014, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 310 nm of less than 0.010, or less than 0.008, or less than 0.006, or less than 0.004.

Embodiment 18

A solvent processed effluent produced according to any of Embodiments 1-17.

Embodiment 19

A formulated lubricant formed from the solvent processed effluent of Embodiment 18, the formulated optionally comprising an additive.

When numerical lower limits and numerical upper limits are listed herein, ranges from any lower limit to any upper limit are contemplated. While the illustrative embodiments of the invention have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth herein but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present invention, including all features which would be treated as equivalents thereof by those skilled in the art to which the invention pertains.

The present invention has been described above with reference to numerous embodiments and specific examples. Many variations will suggest themselves to those skilled in this art in light of the above detailed description. All such obvious variations are within the full intended scope of the appended claims. 

1. A method for making lubricant base stock, comprising: hydroprocessing a deasphalted oil comprising a 370° C.+ fraction under first effective hydroprocessing conditions to form a hydroprocessed effluent, at least a portion of the deasphalted oil having an aromatics content of at least about 50 wt %, the hydroprocessed effluent comprising a sulfur content of 300 wppm or less or a nitrogen content of 100 wppm or less, or a combination thereof; separating the hydroprocessed effluent to form at least a first fraction comprising a T5 distillation point of at least 370° C. and a kinematic viscosity at 100° C. of 6 cSt to 20 cSt; hydroprocessing at least a portion of the first fraction under second effective hydroprocessing conditions, the second effective hydroprocessing conditions comprising catalytic dewaxing conditions, to form a catalytically dewaxed effluent comprising a 370° C.+ portion; and solvent extracting at least a portion of the 370° C.+ portion of the catalytically dewaxed effluent to form a solvent processed effluent.
 2. A method for making lubricant base stock, comprising: performing solvent deasphalting, optionally using a C₄₊ solvent, under effective solvent deasphalting conditions on a feedstock having a T5 boiling point of at least about 370° C. (or at least about 400° C., or at least about 450° C., or at least about 500° C.), the effective solvent deasphalting conditions producing a yield of deasphalted oil of at least about 50 wt % of the feedstock; hydroprocessing at least a portion of the deasphalted oil under first effective hydroprocessing conditions to form a hydroprocessed effluent, the at least a portion of the deasphalted oil having an aromatics content of at least about 50 wt %, the hydroprocessed effluent comprising a sulfur content of 300 wppm or less, a nitrogen content of 100 wppm or less, or a combination thereof; separating the hydroprocessed effluent to form at least a first fraction comprising a T5 distillation point of at least 370° C. and a kinematic viscosity at 100° C. of 6 cSt to 20 cSt; hydroprocessing at least a portion of the first fraction under second effective hydroprocessing conditions, the second effective hydroprocessing conditions comprising catalytic dewaxing conditions, to form a catalytically dewaxed effluent comprising a 370° C.+ portion; and solvent extracting at least a portion of the 370° C.+ portion of the catalytically dewaxed effluent to form a solvent processed effluent.
 3. A method for making lubricant base stock, comprising: hydroprocessing a feedstock comprising a 370° C.+ fraction under first effective hydroprocessing conditions to form a hydroprocessed effluent, the at least a portion of the deasphalted oil having an aromatics content of at least about 50 wt %, the hydroprocessed effluent comprising a sulfur content of 300 wppm or less, a nitrogen content of 100 wppm or less, or a combination thereof; separating the hydroprocessed effluent to form at least a first fraction having a T5 distillation point of at least 370° C.; hydroprocessing at least a portion of the first fraction under second effective hydroprocessing conditions, the second effective hydroprocessing conditions comprising catalytic dewaxing conditions, to form a catalytically dewaxed effluent comprising a 370° C.+ portion, the 370° C.+ portion comprising a second fraction comprising a kinematic viscosity at 100° C. of 6 cSt to 20 cSt; and solvent extracting at least a portion of the second fraction to form a solvent processed effluent.
 4. A method for making lubricant base stock, comprising: performing solvent deasphalting, optionally using a C₄₊ solvent, under effective solvent deasphalting conditions on a feedstock having a T5 boiling point of at least about 370° C. (or at least about 400° C., or at least about 450° C., or at least about 500° C.), the effective solvent deasphalting conditions producing a yield of deasphalted oil of at least about 50 wt % of the feedstock; hydroprocessing at least a portion of the deasphalted oil under first effective hydroprocessing conditions to form a hydroprocessed effluent, the at least a portion of the deasphalted oil having an aromatics content of at least about 50 wt %, the hydroprocessed effluent comprising a sulfur content of 300 wppm or less, a nitrogen content of 100 wppm or less, or a combination thereof; separating the hydroprocessed effluent to form at least a first fraction comprising a T5 distillation point of at least 370° C.; hydroprocessing at least a portion of the first fraction under second effective hydroprocessing conditions, the second effective hydroprocessing conditions comprising catalytic dewaxing conditions, to form a catalytically dewaxed effluent comprising a 370° C.+ portion, the 370° C.+ portion comprising a second fraction comprising a kinematic viscosity at 100° C. of 6 cSt to 20 cSt; and solvent extracting at least a portion of the second fraction to form a solvent processed effluent.
 5. The method of claim 3, further comprising separating at least a portion of the catalytically dewaxed effluent to form the second fraction or separating at least a portion of the 370° C.+ portion of the catalytically dewaxed effluent to form the second fraction.
 6. The method of claim 4, wherein the solvent processed effluent comprises a VI of at least 80 and a kinematic viscosity at 100° C. of 6 cSt to 20 cSt.
 7. The method of claim 1, wherein the solvent processed effluent comprises a pour point of −6° C. or less, a cloud point of −2° C. or a combination thereof.
 8. The method of claims 1-4, wherein the solvent extracting comprises solvent extracting with N-methylpyrrolidone, furfural, phenol, or a combination thereof.
 9. The method of claim 2, wherein the yield of deasphalted oil is at least 55 wt %, wherein the deasphalted oil has an aromatics content of at least 55 wt %, based on a weight of the deasphalted oil, or a combination thereof.
 10. The method of claim 2, wherein the C₄₊ solvent comprises a C₅₊ solvent, a mixture of two or more C₅ isomers, or a combination thereof.
 11. The method of claim 2, wherein the solvent processed effluent comprises a viscosity index of 80 to
 160. 12. The method of claim 2, wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 226 nm of at least 0.020 and the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 226 nm of less than 0.020.
 13. The method of claim 2, wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 254 nm of at least 0.010, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 254 nm of less than 0.010.
 14. The method of claim 2, wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 275 nm of at least 0.010, and the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 275 nm of less than 0.010.
 15. The method of claim 1, wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 302 nm of at least 0.020, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 302 nm of less than 0.010.
 16. The method of claim 2, wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 310 nm of at least 0.030, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 310 nm of less than 0.010.
 17. The method of claim 3, wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 325 nm of at least 0.010, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 310 nm of less than 0.010.
 18. A solvent processed effluent produced according to claim
 1. 19. A formulated lubricant formed from the solvent processed effluent of claim 18 with the formulated lubricant optionally comprising an additive.
 20. The formulated lubricant of claim 19, wherein the additive is selected from the group consisting of detergents, dispersants, antioxidants, viscosity modifiers, pour point depressants, antiwear agents, corrosion inhibitors, rust inhibitors, metal deactivators, extreme pressure additives, anti-seizure agents, wax modifiers, viscosity index improvers, viscosity modifiers, fluid-loss additives, seal compatibility agents, friction modifiers, lubricity agents, anti-staining agents, chromophoric agents, defoamants, demulsifiers, emulsifiers, densifiers, wetting agents, gelling agents, tackiness agents, colorants, and combinations thereof. 